Well, major companies aren't ditching the cloud and there is no evidence for a trend otherwise. And 37signals isn't a major organization for any of the big cloud providers. They are just a rounding error.
They are certainly a household name in the startup community but they are not a major organization for the big three cloud providers. Why is this important? Because the headline claims falsely that major companies are ditching the cloud providers. I have insights into the decision process for a major organization moving to the cloud and the motivation why 37 would leave cloud are in no way comparable to that of a major org.