Existing HPC projects (aka "supercomputers") show that money is available for hardware-intensive research projects (perhaps the lesson here is that the US needs

Existing HPC projects (aka "supercomputers") show that money is available for hardware-intensive research projects (perhaps the lesson here is that the US needs an AI/ML focused National Lab), and as far as the cost of creating a bespoke cluster for a single project, I think that running it full bore for a project and then selling it off ASAP would avoid most of the downsides you've mentioned. Again, I have a feeling that big-budget render farms have trod this path before.