I could still see some buildings popping in.
Thing is, the comparison is a bit off. That's what the PS5 could do ... using the same graphical settings as the PS4 does.
That won't happen though since devs are going to push the PS5 which will then lead to longer loading times.
Looking back, how much have loading times improved throughout the generations? Answer: not much.
I guess it really depends on how the hardware is utilized. In terms of the ability to load data off of a piece of physical storage, these times have increased dramatically over the years, but there becomes a point where waiting for a game to load becomes unacceptable and a game "loses points" because of it. I think this amount of time has decreased over the years. During the PS1 era I had a pinball game that took (from my probably skewed memory) about five minutes to load a small pinball map.
But if you look at Nintendo, they seem to minimize load times very well in most of their games. Some games have them, while others load fast enough that it doesn't warrant a load screen in itself.
As a kid, I always thought the Gamecube had such fast loading times because the disks were small, and I made those assumptions based on playing games on both systems and noticing that Nintendo games didn't seem to require loading.
But circling back to your point, I totally agree. Similarly, it bugs me when people say "will next gen be able to handle 60 FPS", when that is a meaningless metric to determine the power of a system. The NES had games run at 60 FPS.