HBM is just normal DDR RAM that's been packaged with (much) wider-than-usual data buses. That's where the high bandwidth comes from, not from high clock rates or any other innovation or improvement in core specifications.

Very few applications other than GPUs need HBM.

AMD has built some consumer GPUs in the recent past with HBM - RX Vega and Radeon VII (although I assume not all "HBM" is created equal).

Anything where there's _at worst_ solder and traces between the compute and the memory. That's why you see it on GPUs (and Apple hardware). DRAMs advantage is modularity.

At least as I understand it.

I think the datacenters will simple be repurposed for hardware as a service, specially cloud gaming, sense it will be to expensive to buy a new computer anyway.

They can just switch back to normal DRAM if HBM demand drops, you ain't getting it cheap just coz AI flops