There was an article on Hacker News just the other day explaining that no one knows what the value of these used GPUs are going to be and that people underwriting are just, essentially, just guessing.

Here is the link (oddly I could not find it with HN Search): https://news.ycombinator.com/item?id=48917135

Growth of what exactly? AI doesn't have the normal leverage factor that software usually does where a simple codebase can drive a billion dollars of subscription revenue with 90%+ gross margin. There's no eventual state where the capex is in place and the margins flip. They're in the datacenter business, which is real estate, with tenant improvements consisting of rapidly depreciating/obsoleting equipment. These margins have no path to flip around and allow for a huge amount of revenues to flow through. If they start testing price sensitivity in the way that would justify the valuations, it will just accelerate the transition of AI from datacenter to local.

>Experts continue to warn of an AI bubble, noting the enormous and widening gulf between company valuations and their comparatively measly profits

The pertinent comparison in valuations is debt vs equity, not debt vs cash as you noted.