Colo and cloud providers that provide real SLAs exist. But they're pricey because they tend to insure against breach of that that SLA and they pass on the cost of that insurance. If you're a run-of-the-mill e-commerce company then it probably doesn't make much sense. But if you yourself are providing critical services to others and they have you by the short hairs in case you don't perform you better make sure that you're not going to end up holding the bag.

One simple example: energy market services, 15 minute ahead and day ahead markets require participants to have the ability to perform or they will be penalized severely, to the point where they can lose that access, the damage of which could easily be in the 10's of millions to 100's of millions depending on their size. Asset owners and utilities both would be able to hit them hard if they do not perform, the asset owners for lost income and the utilities for both government penalties and possibly for outages and all associated costs. These are not the kind of contracts you enter into lightly.