With NVidia/OpenAI actual graphics cards did change hands. Vendor financing, like when a car dealership gives you a loan to buy a new car, is actually pretty normal.
With chip development you need scale in order to get to the edge. It makes sense to finance demand so you can get to scale it's not like it's a ponzi scheme.
Anthropic gets access to limited compute resources and Amazon gets demand to justify increased R&D and capex + feedback from the best users in the field.