There would be no need for altcoins to exist
There is a very apparent reason why altcoins exist: We don't need to come into one agreement, if some of us disagree with each other. Remember: coercion holds no sway in this space. I cannot force you follow my proposal for 100 MB block size. I can only implement it, and invite you to join.
Bitcoin is ingenious technology because it gives you the freedom to define it yourself. If you think Bitcoin has failed, it's because you've overlooked at this feature. But, let me ask you this question: What should the Bitcoin developers do, if not keep it "at certain version", as you claim? What should it change, in your opinion, so that it would make it thrive?
First off, the halving should stop - this leads to tail-emission.
This approach would give more assurance for security, why it's in danger with current scheme I have already explained.
Block size should be dynamic and not static so the fees would not skyrocket and block poor people from using or even withdrawing their money.
If this two things were fixed, Bitcoin would make sense as an alternative to fully obfuscated chains.