Stop right there! There is plenty of evidence that removing features from a language is fatal to adoption. Both Perl and Python have suffered from this.
Specifically for trigraphs (apart from these, EBCDIC support doesn't affect compilers on other systems) IBM have a vote and they voted not to remove it: https://isocpp.org/files/papers/N4210.pdf
How has Python suffered from this? They broke things going from 2 to 3... and it was still the fastest growing language from 2017.
It clearly wasn't popular just because they removed features, but you can't say that removing things is fatal to adoption.
Stop right there! There is plenty of evidence that removing features from a language is fatal to adoption. Both Perl and Python have suffered from this.
Specifically for trigraphs (apart from these, EBCDIC support doesn't affect compilers on other systems) IBM have a vote and they voted not to remove it: https://isocpp.org/files/papers/N4210.pdf