Don't think it will happen soon. Phone numbers have the advantage that they are harder to misuse than email addresses while being partly anonymous and company independent. Furthermore, you can provide some identification without using another password. Nearly everyone has one and you have a 1-1 relationship to (most) phones. I actually think that phone numbers will become more important with more apps using it as an account (e.g. Google Duo).

I hope that never.

Getting a prepaid SIM card with a number I have power over to disclose to only whomever I want is still great in my book.

Except that there's a huge security whole (SS7) in the phone networks and it's been there for years. https://www.youtube.com/watch?v=dDCYlGX22Q0