That's a little bit different. I would assume Google grows GCS over time to meet demand. Most of the demand is static. If Google needs 1PB of storage, they will probably have 1.01PB, and the amount won't go down.
Compute is dynamic. You might be above capacity for Christmas shopping, and below capacity at 4am in the middle of the weekend.
By varying pricing, you can be more efficient. People who can will smooth out that load. If I don't need to run something during peak hours, I might wait until off-peak. Google needs less capacity. Everyone comes out ahead.
For a profit-making project, dynamic pricing makes sense. I suggested free since the primary goal of co-lab isn't to make money (but they also don't want to subsidize it too much, so they do need to charge).
AWS and GCP have spot pricing on VMs, so they do have products that do this.
Maybe that's enough. When Colab load goes low, they can turn down a bunch of Colab tasks, and sell the freed capacity as Spot VM / preemptable VMs.
I'm sure there are many big companies out there that essentially have a standing bid for any compute cheaper than $X, and will soak it up as Spot VMs.
Not every GCP product needs to have spot pricing to be efficient. In fact if you silo capacity per product then you'll be less efficient. E.g. someone is willing to pay for spot VMs, but you only have spot Colab available.
Compute is dynamic. You might be above capacity for Christmas shopping, and below capacity at 4am in the middle of the weekend.
By varying pricing, you can be more efficient. People who can will smooth out that load. If I don't need to run something during peak hours, I might wait until off-peak. Google needs less capacity. Everyone comes out ahead.
For a profit-making project, dynamic pricing makes sense. I suggested free since the primary goal of co-lab isn't to make money (but they also don't want to subsidize it too much, so they do need to charge).