A Valve engineer fixed 3D lighting so hard he had to tell all the graphics card manufacturers their math was wrong, and the reaction was: 'I hate you'

Hardware takes a long time to change.

A temporary patch while we wait for hardware is the way to go.

Nothing is more permanent than a temporary fix.

They already fixed it in software we don't need to prioritize the hardware fix.

"the garbage trend is to produce a noisy technique and then trying to "fix" it with TAA. it's not a TAA problem, it's a noisy garbage technique problem...if you remove TAA from from a ghosty renderer, you have no alternative of what to replace it with, because the image will be so noisy that no single-shot denoiser can handle it anyway. so fundamentally it's a problem with the renderer that produced the noisy image in the first place, not a problem with TAA that denoised it temporally"

(this was Alexander Sannikov (a Path of Exile graphics dev) in an argument/discussion with Threat Interactive on the Radiance Cascades discord server, if anyone's interested)

Anyways, it's really easier said than done to "just have a less noisy technique". Most of the time, it comes down to this choice: would you like worse, blobbier lighting and shadows, or would you like a little bit of blurriness when you're moving? Screen resolution keeps getting higher, and temporal techniques such as DLSS keep getting more popular, so I think you'll find that more and more people are going to go with the TAA option.