Intel and AMD also do support unified memory for their integrated graphics. It’s been a while since you needed a statically cordoned-off area of main memory (“shared memory”) for the iGPU to work.

Consoles have been using unified memory since the 8th gen (PS4/XB1/Switch, kinda sorta even WiiU).

And NVidia has CUDA unified-memory slide decks going back at least 5 years.

The Xbox360 already had unified memory too. That gave it a slight edge compared to the PS3 in the long term because it was more flexible compared to a fixed 50:50 split.

The original xbox before it too.

And the N64 before them. I think it was the first console with unified memory.