People talk about difference in resolution and color depth? 640x480x16 isn't that much less than 1920x1080x32. My current resolution has 13 times more data than my 1995 one, and my HW can handle refreshing it 120 times per second and fill it with millions of beautiful anti-aliased polygons all interacting with each other with simulated physics and dozens of shaders applied calculating AI behaviour, path finding, thousands of RNG roll, streaming data to and from disk and syncing everything over the network which is still limited by the speed of light. As long as I play Path of Exile that is.
Opening desktop software is perceptually the same as in the 90s. From launching to usable state is about the same amount of time, and it's not doing so much more that it can explain why current software takes so long.
If I can play Path of Exile at 120fps it's obviously not an issue of HW scaling or not being able to achieve performance.