I was also a PS beta tester around that time, and prominent testers such as Stu Maschwitz were actively pushing the PS and After Effects teams to incorporate li

I was also a PS beta tester around that time, and prominent testers such as Stu Maschwitz were actively pushing the PS and After Effects teams to incorporate linear light compositing. 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.