Notably there's something like an order of magnitude or more difference in performance between terminals that people are perfectly happy to use. (EDIT: To quantify this: on my system, catting the same file to a window taking about half my screen took an average of 1.443s with st, 1.16 seconds with xterm, 0.165s with rxvt xterm, and 0.404s with Kitty - all average over 3 runs)

Very few non-gpu accelerated terminals get anywhere near maximising performance and they're still fast enough that most people don't even notice because most applications, including most editors, once even remotely optimized themselves, don't tend to push even a non-accelerated terminal very hard.

Put another way: a typical test case of the performance of a terminal tends to be spewing log output or similar to it at a rate where the obvious fix is to simply decouple the text buffer from the render loop because nobody can read it all anyway (but really, a lot of the developers of these terminals should start by looking at rxvt and at least get to a decent approximation first before they start doing those kinds of shortcuts)

Fast enough terminal rendering was solved by the mid 1980s, and performance increases have outpaced resolution increases by a substantial factor.