I'd disagree with this lesson. Saying "do not utilize cloud solutions" period is nuts. Google and Microsoft are way better at email hosting and delivery than your on-prem server is unless you spend a ton more money on hardware and engineers to keep it up, which is simply not worth it for many companies. Dropbox is going to have better uptime and lower TCO than your self-hosted owncloud instance.
What I will say is it's important for the customer to HAVE THEIR OWN BACKUPS. Don't rely on the vendor - that's the lesson here. If you have all your stuff in AWS back that data up someplace that's not AWS, etc.
On prem outages and data loss happens constantly. Much more than cloud hosted issues. They just affect a smaller group each time. It's like how people view the countless car crash deaths as non issue but freak out over a rare train crash.
Have your own backup works only if there are common open standards for export/ import. Email or storage may have those, project management tools don't. I can't simply backup from Jira and start using pivotal.
Even for Email or storage or any other open system, UX changes and feature differences can take a lot of time to train properly, you don't migrate from one vendor to another vendor just like that.
Edit: to clarify I would say if the data is important to you, then “the ability to back up the data” should be a requirement when selecting saas. See my other comment in this thread on ms planner.
