Possible doesn't mean it's probable.
I agree with you, don't get me wrong. I am very sure that it's nearly impossible to reverse a public key to private, I'm talking theoretically, what would happen in that case. It may be in 2040, or in 2140, but there will be sooner or later a year in which quantum computers or any other advanced technological creation constitutes a threat to the current hashing algorithms.
Let's hope SHA-256 is still strong enough in the next 20-30 years.
RIPEMD-160 is the one we should hope for. It's 2
96 "weaker" than SHA-256.
The term "real bitcoin" is ambiguous, what defines it?
True, it's ambiguous. But I don't blame that they'll change the
"real bitcoin", neither that they'll increase the 21 million limit. I'm in favor of the bitcoin's principles, I'm just wondering how can they make such change. A bitcoin node should be running forever if possible. But any node that'd do that since 2009, would not follow the correct change at the moment. The current chain would be considered invalid due to SegWit.
My conclusion is that the developers won't force you
directly. But they will.