I think people are making a bad assumption that features = profit, and that we're going to be trapped in a red-queen race to move in place while shipping features at an astonishing rate. I don't think this is going to happen.

Before subscription services, you needed to add features because you had to justify to people why they should buy an upgrade. So yeah, it made sense to make as many features as possible to try to cast a wide net.

I think with software as a service, making features is not really the most important thing. Realistically, people buy software for what it does right now, not its future potential. Further, changing things out from underneath users tends to annoy them (pretty much EVERY time a service introduces a redesign, even if it's a good one, people initially hate it -- you're asking them to relearn a thing that was working perfectly fine).

Anyway, I think new software is going to win the same way it's always won, based on its utility, not based on shipping features at some sort of frantic rate.