Its a "fundamental principle" of the Bitcoin community yes, its strongly held as one of our core tenets. But it could still be changed. So stop saying its limited without pointing out what its limited by.
Well I would like to also point out that if the 21 million cap limit was increased then what we have is no longer Bitcoin.
Even if 99.97% of the users still call it "Bitcoin" it won't be Bitcoin to me. It would be a PoS coin. Not proof-of-stake, but piece-of-shit.