I'm definitely not saying that it's an easy undertaking but while the excuse was much more valid in 2007 it just doesn't work for me here in 2020 with the likes of a i9-10900K combined with a RTX 3080 out there. If the work wasn't going to be done (or couldn't be done) to get the CPU optimization up to speed for multi-cores then the effort is almost pointless as while the game still looks good and some of the Remastered visuals (RTX, increased texture res, etc) look better it simply doesn't have the visual splendor of a game performing as badly as it does.
I have the game running pretty good with RTX set to high (could be my current level in the game too as it's obviously inconsistent) but, again, we should be able to finally get close to maxing this game out with great performance and that's simply not the case....unfortunately not even close.