They want to do that themselves, and keep the customer relationship and the profits, instead of giving them to a middleman or the customer.
You can rent a 2-socket AMD server with 120 available cores and RDMA for something like 50c to $2 per hour. That’s just barely above the cost of the electricity and cooling!
What do you want, free compute just handed to you out of the goodness of their hearts?
There is incredible demand for high-end GPUs right now, and market prices reflect that.
It's just business and I'd do the same if I was in charge of AWS.
The instances with the 4th generation "Genoa-X" processors (HB176rs_v4) cost about $2.88 per hour. The HX176rs_v4 model with 1.7 TB of memory is $3.46 per hour.
https://learn.microsoft.com/en-us/azure/virtual-machines/hbv...
https://learn.microsoft.com/en-us/azure/virtual-machines/hbv...
https://learn.microsoft.com/en-us/azure/virtual-machines/hx-...
Source required
A large part of the profit comes from the upfront risk of buying machines. With this you are just absorbing that risk which may be better if the startup expects to last.