How will the disadvantages of blockchain affect the efficiency of enterprises?

Question

blockchain

It will be more about the enterprises of the tourism industry. The news is full of calls to transfer business to the blockchain, but not everyone writes about the shortcomings of the technology. After digging into various studies and reading about the main problems, I roughly understood who benefits from using the blockchain, and for whom it is a waste of time and resources. However, open questions remain:
1. The question of cost-effectiveness.
Currently, it is quite difficult for new companies to enter the market, and even if they do, they can be squeezed out by large chain companies, and GDS (global distribution systems) and online booking giants can impose unrealistic conditions for work. Startups are already emerging offering to solve their problems by switching to the blockchain.
As far as I know, a distributed database, due to its nature, takes up a lot of space, which makes it very heavy, and therefore also expensive. Do I understand correctly that, for example, a new mini-hotel to work with transport companies will have to download the entire huge database of these companies to create their own node? And also because of the nature of the blockchain, will this new mini-hotel have access (or just the ability to view) all the other partner hotels of these transport companies, their transactions, financial status?
The costs of introducing this technology may affect the increase in the cost of products / services of new market participants in the same way as the commission of the GDS and other large partner companies. Will this choice be more optimal / more promising / more profitable than the traditional one for new participants and for the rest?
2. The issue of privacy.
Suppose a certain tour operator nevertheless switched to a public blockchain and now all operations with clients/partners/suppliers are carried out through this system. Does this mean that all confidential data (passport data, wages, trading operations of companies, bank account details and financial status at any time, etc.) of each user (both companies and tourists) will be open to everyone else? If this is an open blockchain, then this data will be available to everyone in general, not even to users of this particular system? Will a private blockchain solve these problems?
If the system does not store the documents themselves, but only the codes proving the fact of the existence of these documents, who and how can these documents be seen/downloaded/copied apart from their owner and recipient?
3. Question about changing blocks/data/something.
No one excludes the human factor, errors are possible at any time and in any operation. Will it be possible to change/correct/delete any information or operation when working on an "open consensus model" platform rather than a centralized one? If yes, how will this happen?
4. Question about "attack 51%".
When introducing blockchain by enterprises (both new and small, as well as market leaders), it is possible to transfer the entire existing situation to another environment that is not yet regulated by law. So, the same large hotel chains (InterContinental, Marriott, Hilton, which own many hotels and under other brands), GDS (of which there are only a few) will have the possibility of a cartel that is not subject to the state and legislation.
Is this an erroneous opinion, or is the danger of an oligopoly much higher when switching to blockchain?
5. Question about logging out.
What will happen to information about an enterprise or other user who decides to stop working through the blockchain? Will all information (including confidential) be preserved and remain available forever? Until when does this distributed database exist and when can it cease to exist?
6. The question of contingencies.
So, for example, global natural and climatic problems (lightning / storm / hurricane) can overtake at any moment, so that access to the Internet network or an identification number for a long time (or forever) will be lost by one node or a whole group of nodes (or in the case of private blockchain system, for example, all nodes in general). In this case, will they be able to regain their previous access to the database as a former member? Or will they have to log in as new members? Will the branches of chains associated with these nodes die off or will they remain as dead ends?

Answer 1

I also tried to understand what kind of noise, and I understood it this way.
Blockchain is a technology that allows you to ensure that:
1. this piece of data appeared here for a reason
2. it is now exactly the same as at the time of its appearance.
This is, in fact, the only advantage of technology.
Further, they add to it:
3. the ability to store data anywhere - we can guarantee that they have not been changed. However, the question immediately arises - who and why will do this? Cryptocurrencies provide the answer to this question. Distributed systems within a bank or between banks - too, if the banks themselves have such an interest.
To plant an entire industry on this - but for what, in fact? Blockchain does not imply any revolutionary solutions, it is pure parasitism on a fashionable topic.
Privacy issues and other questions that beginners have are not really critical - the data stored in the blockchain can be arbitrarily open, but if this data is encrypted and can only be opened with a key, the difference is with a database, access to which requires exactly the same password key , is minimal.
Changing data on the blockchain simply involves adding a new, changing record. What is preserved and incorrect - well, this does not interfere with Wikipedia, for example.
A cartel collusion of major players, IMHO, is less likely than another rage of a rabid printer. Yes, and this is primitive - they just need to break the working system in the last place.
Dead branches, of course, must be cut off and destroyed. But after all, the data does not have to be continuous chains. We create nodal blocks of trust - and we can "drop" everything that was between them. Or a tree of chains growing independently of each other.
In general, many problems are contrived due to a lack of understanding of the place of the blockchain in the system. This is a deep level, data storage. There can be a hell of a lot of add-ons above it, just like a database. The main thing is to formulate requirements. "Save us, blockchain, from the evil one" - this is not a requirement, if anything;)

Answer 2

Dear, you did not understand the essence at all. The bottom line is to make a beautiful ICO, with a powerful website and beautiful Facebook profiles, take a ride on a couple of blockchain "conferences" and then fuck the brains of "investors" for about a year with a simulation of vigorous activity. And here you are worried about 50 + 1 attacks and cataclysms with the "die-off of a chain branch", well, by God, what a naivety.

Answer 3

Mouse edren .... Mnogabukaf. Very many books. Do you seriously think that there will be people here:
- who are so closely related to the tourism industry that they understand the specifics of the problems
- who have the desire to read this entire stream of consciousness in order to give a meaningful answer to it
Blockchain is a hype, but little explored system. As far as I understand it, everything that is thrown into it remains there forever and is available to everyone. Anonymity here is manifested in the fact that it is assumed that it is impossible (which of course is not) to establish a connection between a nickname in the system and a real person, but these are not blockchain issues :)