I wouldn't even buy new hardware. I would buy retired hardware for a fraction of the price.

I would imagine that managing such a pool of dated and highly heterogeneous hardware would incur a lot of overhead. The procurement effort may end up being rather high as well.

yet a number of FAANGs have datacenters full of mismatched lease returns. So it much make sense at some scale.

The possibilities do seem rather endless. This could very well be the backbone storage layer for may popular sites such as youtube or netflix, imgur etc. Decentralization eliminates a single point of failure.