Ask yourself why VRAM continued to grow
Cause the GPU world was moving on? PS2 certainly wasnt anything forward, it reminds me of the very fast SGI systems with their multipass bruteforce of the mid 90s i think it was.
4x dvd wasnt fast even then, i remember having a Acer 16x dvd drive in my pc by then (around 2000). Maybe fast enough for its intended application but you sound like it was the PCI-E SSD of 2000
Just look back at how often there was load points in PC games back then.
Loading points/times werent exactly PS2s strong point, it was one of the worst experiences ive ever had regarding load times. Blame the 'lazy' devs or whatever, but anything loading wasnt anything to brag about on PS2. On pc (and xbox) loading times and points where less/faster.
MGS2 and GOW wasn't particularly impressive technically. They had some nice art techniques, but they did not push the hardware in any kind of way.
Again as I wrote earlier, very few games did for a number of reasons.
Some of the most impressive, or at least the ones that uses some of the unique power in the PS2 best is Burnout III, Shadow of the Colossus and Okami.
MGS2 and GOW where about the max of the PS2, GOW2 wasnt that much better then GOW, not worlds different, and GOW2 pushed PS2s limits for sure.
You say GOW was about art, but many have said shadow of the colossus was more about art then technical, SotC could really struggle on the PS2 btw, almost unplayable, i mean 20fps or below it felt like.
The CPU core combined with the VU0 either in slave mode or not was a very powerful CPU for its time.
If like Exophase (and others have said), a nerfed 733 P3 from the xbox is faster then the CPU of the PS2 (thats VU0/EE, VU1 must help out GS for being a full GPU), that means pc of the time, a 1ghz P3 or even better, athlon thunderbird over 1ghz would be whole lot better then PS2 CPU.
Then we have left GPU chip, for PS2 that is GS + VU1, for pc that would be something like a Geforce 2 GTS or ATI R100. Im not an expert, maybe others can answer, but i think any of those GPUs would fare better in most games. Perhaps miss some effects but better at other departments. With in the end the pc in total being able to output better games graphically, not talking about optimizations.