Also, focusing on ASCII often means implicitly focusing on English keyboards to the detriment of other languages.

The ^ and ~ characters are particularly hard to type on many European keyboards. My MacBook's Finnish/Swedish keyboard doesn't even show the tilde ~ character anywhere on the physical layout, and it requires three keypresses to type.

I'm not sure that it's survivor bias. Besides, ASCII's long survival is exactly what makes it so important. ASCII has endured for so long, and is embedded in so much software and even some hardware, that even if ASCII is abandoned for a better encoding, there WILL be legacy support for it. You can never be sure that a data format will endure, but ASCII is about as close to that certainty as you can get.