How to make SMS confirmation in google mail gmail?

Question

Google

Anyone who has access to the account can change the number to their own. In this case, you just need to enter a new phone number and confirm it.
https://myaccount.google.com/phone

Why is there no SMS confirmation for the old phone number and how to enable this confirmation?

Answer 1

And how will someone get access to the account if they don’t tell him the login / password?)
Because everyone doesn’t care about your acc. He doesn't have to be protected. Number binding exists to cut off spammers