Does it make sense to study such microsoft products as SharePoint and skype for business?

Question

Microsoft

Good day! Colleagues who are involved in infrastructure projects based on Microsoft unified communications, a question for you.
I am no longer at the start of an IT career, but I have not gone far from the start. Now I choose to specialize in several areas. In this regard, the question is: does it make sense to study products such as SharePoint and skype for business? Will these technologies be in demand in 3,4,5 years? Will it not turn out that sharepoint will be replaced simply by an internal site on apache and joomla, and 90% telephony will be done through sip providers or some kind of google meet? And will it not turn out in the end that the knowledge gained will not be in demand and it will not be possible to sell it?
And how are the company's internal sites doing now? (do I have to talk about replacing sharepoint with some cms)
PS. Separately, who knows, write about the competition between skype for business and asterisk, please.

Answer 1

The internal site on Joomla under Apache will not be replaced for a very long time.
sharepoint is quite a useful product, and if it is already implemented, then it will not be changed soon. Entering from scratch is not a fact, there are options.
And skype for business is just pretty good.
But again, such - these products - for large companies.