What kind of consumer electronics can you build with HBM? That's the startup you should be founding...
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.
[dead]
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).