I heard explanations how it'd be slow, or doesn't matter, or what am I talking about, all ultimately variations of "works as coded, won't fix".
There are clearly people at Adobe who are aware of the issue in some capacity, and their efforts have weird specifics, such as... they noticed text anti-aliasing looks weird, so they added an Advanced Control called "Blend Text Colors Using Gamma" option in Color Settings. The bizarre thing is that none of this is specific to text. It's just that text has many small complex shape edges, and you notice it more on text (like Carmack noticed it on the star field). They didn't fix vector art rendering, for example. And the option default is not even the correct gamma for a document, but 1.45 which makes no sense at all. They just "eyed it" and went with it.
There's also a Blend RGB Colors Using Gamma option which is disabled by default. If you enable it, it corrects SOME operations, but not others, with no rhyme or reason. However, you can't really tweak those yourself, because if you do, the settings are not saved per document, they're global. So if you tweak them... then ALL Photoshop files you open will look wrong, because they were originally made for another configuration of these settings. Which leaves you with 32-bit color channels. I have Actions that convert an image to 32-bit to scale, and back to 8/16-bit, just so it's gamma corrected.
It's... a f***ing mess.
"Photoshop antialiases text using γ=1.42 by default, and this indeed seems to yield the best looking results (middle image). The reason for this is that most fonts have been designed for gamma-incorrect font rasterizers, hence if you use linear space (correctly), then the fonts will look thinner than they should."
https://blog.johnnovak.net/2016/09/21/what-every-coder-shoul...
So even if a font is designed with incorrect gamma, it might still not be the best to render it with incorrect gamma, as you might use different background and foreground colors to the designer of the font.
AFAIK freetype has the option to enable "stem thickening" to consistently correct for incorrectly designed fonts regardless of colors being used for rendering.
Stu was able to get linear compositing into AE, but I think PS had already evolved into more of a graphics tool than a photo tool. They added 32bpcc and HDR, but it's for specialty workflows, not general use.
Fully embracing linear light would change almost every part of PS—everything from blend modes to the built-in filters were written for perceptually encoded values that don't go over 1.0. Even today, Curves works with 32bpcc, but only shows you the 0–1 portion.