Sure they can: if you lose half your users because of economic downturn, you don’t need half your compute.

You may want to reconsider this assumption. The cloud companies may be relatively "recession proof" because more companies are migrating to the cloud.

However, their customers are not. I've helped several companies reach 80%+ reductions in compute/storage needs, which then translates into similar cost savings. No reservations needed, you have to provide deeper value and changes to achieve this.

> Usage does take on all the risk.

Seems like a great way to get 3-year commitment prices without the risks. Are you worried about assuming all that risk? What about abuse of this relationship by your customers?

This assumes all compute was crucial for business operation. In practice however, a lot of compute volume just serves expendable reasons such as for example marketing people trying to data-mine interesting leads out of terabytes of sales data. Stuff you do, as a company, while you're flush with cash and thus ready to spend some on potential opportunities. These things however are the first projects to be cut when times are getting rough and budgets must be tailored down to survive.