It's not even just standards changing, this isn't what RE4 looked like on release on gamecube
It looked much more like these:
The texture quality looks much more cohesive when matched with the lower resolution, and analog video output of the GC. The game looked amazing for its time, and I think still looks really great on original hardware. The PC version is awesome in a whole different way, and with this texture pack especially it's a HUGE improvement. But we shouldn't be falsely convinced the game wasn't originally great looking, because looking at it still now it looks good.
A great example is this notorious screenshot of the game before launch on PC.
Look at the faces of the dudes further back. That sticks out like a sore thumb, and is REALLY noticeable.
In comparison, this is how it looked on GC.
Nothing looks out of place. I'd probably even say this example looks better on GC (even though it is blurrier. )