The wondrous thing here is that we've seen this exact same thing in the past, but people are still building castle in the sky ideas about what'll happen this time around. The PS3 on paper was quite a bit more powerful than the X360 - IF you chose to fully indulge in their hardware choices, use all the SPUs, etc. But there was a lot of cost and development time involved with that. So what did Third Party's do? They completely ignored the extra potential power the PS3 might have had and instead opted for developing the same game across multiple platforms: PC, X360, PS3 at the time.
Now, don't get me wrong, I'd love for the SSD speeds the PS5 will apparently have to be the standard for all devices, but that just won't be the case. So my guess is that we'll see the PS5 winning in terms of loading times and the X1SX usually featuring higher resolutions and / or better framerates. And then it's up to gamers to decide what's more important to them. But will third party devs significantly alter their games to fully make use of one particular hardware config? No, of course not. It's hard enough to design great levels as it is, the last thing you want as a developer is to now having to change content just because potentially on some hardware you could stream things in instead of showing a loading screen. The more realistic thing to have happen here is that most third party devs will still opt to show the loading screen, but it'll take 5 seconds for X1SX to load the next batch of content, whereas the PS5 only needs 3 seconds. That's it.
