I'd imagine all of the vendors have an incentive to keep their main customer a float, while there might be penalties etc. for missed targets - it doesn't make sense for any of these vendors to ride the contract into chapter 11.

This is so important in analyzing these commitments. Anthropic's commitments will make them a Top 10 customer at many of their vendors. (Even at Google/Amazon, how many other customers do they have with $100B+ committed?)

Those vendors would very much like to retain as much of that business as possible. If the space goes sideways, I would very much expect some kind of renegotiation/work out.