Flipping works great in a rising market. It's a lot harder when the market slows. All these companies got in just as the market was turning directions. Additionally, even in the best of markets you can't just buy,fix and sell at a profit. You have to pick the properties carefully.

I suspect a lot of the properties that were bought were bought to fill some kind of goal for the period rather than they having profit potential.

The better investment is buying, renting and then selling a decade later. The idea is that the renter pays the mortgage and other expenses for the property. But that's too long for most companies.