That Mario 64 demo does use the expansion pack, and a lot of games that did too had access to 2-4 times higher resolution options even if the expansion pack wasn't mandatory. That is kind of huge.

It is my understanding that their esoteric 9-bit Rambus RAM was way faster than the PS1's EDO RAM, but the CPU and GPU would fight over access to it so unified memory wasn't as optimal back then as it would in the X360 days.

Ideally, they probably should have done away with the cache (which is still RAM, mind, SRAM) and included some 4MB of dedicated VRAM. Even without the benefit of hindsight, I don't think developing that kind of solution was out of reach for Silicon Graphics considering the PS1/Saturn opted for this.

6th Gen Graphics (especially cutscenes) were the first time I can think of where the graphics looked even somewhat like Toy Story (1995). 

None of the 5th Gen games I can think of match movies like Toy Story, A Bug's Life, and Toy Story 2. 

Mega Drive to Saturn closely followed by SNES to N64. If Switch is considered a successor to the 3DS, then it wins by a mile.

Hard disagree here. The Nes delivered masterpiece after  masterpiece  as well and was a much more revolutionary system.

Ironically the tie-in games for all those movies were part of the 5th gen of games

Yeah, cutscenes especially going from 5th gen to 6th gen was insane! One of the biggest comparisons I've seen was going Final Fantasy 9 to Final Fantasy 10. And that was literally just a year apart!

Going from SNES to N64 was absolutely a huge jump but honestly every system going from 5th gen to 6th gen would have my vote. Even the Dreamcast. 

Nice to see Sega get a shoutout; the jump from 2D to 3D was monumental for them as well, even if the system didn't have the same impact that the N64 did.

Saturn to Dreamcast was also a massive leap considering the came out only 4 years apart.

Funny thing is I had a dreamcast but for some reason ps2 blew me away more. Certain games like mgs2 trailer and gran turismo 3 had my jaw on the floor, heck I owned a Xbox as well and resident evil 4 on ps2 impressed me more then anything on Xbox just shows how important art style is. I never saw resident evil 4 on GameCube but that must have been a sight to behold back then. Easily the best looking game of that generation imo. I think in that generation ps2 introduced new lighting  tech while dreamcast did not.

If you watch the video it goes in-depth on the CPU/GPU contention issues when accessing Ram.

And yes, the expansion pack was used by a plethora of games... To various degrees. I.E. Donkey Kong used it to get around a memory leak bug.
But I wouldn't consider additional Ram beyond that to be a "memory starved" ecosystem, it was limited in other ways before that became a big issue.

They didn't even need to skip the 4kb of texture memory or replace it, they just needed to let developers bypass it entirely and access straight from cart or system memory.

Atari Home Pong (1975) to Atari VCS/2600 (1977) - take 2

Pole Position (2600)

Solaris (2600)

I'm not an expert but as far as I'm aware, Dreamcast did introduce new lighting tech; it was just less powerful than PS2 due to releasing over a year earlier, and didn't stick around long enough to benefit from a lot of the technical advances made during that generation.