The problems with closed-source software (lack of control, lack of reliability) were solved with a new business model: open source development, which came with new licenses and new ways of getting revenue (maintenance contracts instead of license fees).
In the same way, we need a business model solution to cloud-vendor ills.
Imagine we create standard contracts/licenses that define rights so that users can be confident of their relationship with cloud-vendors. Over time, maybe users would only deal with vendors that had these licenses. The rights would be something like:
* End-of-life contracts: cloud-vendors should contractually spell out what happens if they can't afford to keep the servers running.
* Data portability guarantees: Vendors must spell out how data gets migrated out, and all formats must be either open or (at minimum) fully documented.
* Data privacy transparency: Vendors must track/audit all data access and report to the user who/what read their data and when.
I'm sure you can think of a dozen other clauses.
The tricky part is, of course, adoption. What's in it for the cloud-vendors? Why would they adopt this? The major fear of cloud-vendors is, I think, churn. If you're paying lots of money to get people to try your service, you have to make sure they don't churn out, or you'll lose money. Maybe these contracts come only with annual subscription terms. Or maybe the appeal of these contracts is enough for vendors to charge more.