So there literally were no "loading" times for these assets. This might not even be realistically possible with NAND flash based SSDs, e.g. because of considerations like latency.
Though directly accessing ROM memory would also prevent things like texture block compression I believe.
Small RAM space with the hard CPU/GPU split (so no reallocation) feeding off a slow HDD which is being fed by an even slower Bluray disc, you are sitting around for a while.
Excessively high detail models require extra artist time too.
The only thing I value is a consistent stream of frames on a console.
From PS5 Pro reveal https://youtu.be/X24BzyzQQ-8?t=172
I wonder if players of single player action/adventure games make the same choice. Those games are played less (can be finished in 10-30 hours instead of endlessly) so the statistics might be skewed to favor performance mode.
Anecdotally, I do. Because modern displays are horrible blurry messes at lower framerates. I don't care about my input latency, I care about my image not being a smear every time the camera viewport moves.
I'm sure it would have been even more successful with modern 60 FPS, but that difference couldn't have been very large, because other 60 FPS games did exist back then as well, mostly without being nearly as popular.