An SSD on PC is definitely a step up from anything before this gen.

This gen (at least PS5, which leans hard into the tech with hardware decompression on top of the silly raw speed of the drives) is better than PC, though (for now). The hardware you're buying now can do pretty much everything the PS5 hardware can, but because the software stack to use it isn't the same and universal, there's definitely more loads. It's similar to how PS4 games load fast (especially compared to on the actual PS4), but get blown out of the water by PS5 games. I die in Horizon: Zero Dawn, it's 5-10 seconds. Which is fine. But I die in Forbidden West, which is prettier and has more complexity (mechanically and the environment) and it's maybe a second.