Yes, I've been saying this for some time. What's even more amazing is that relatively new disruptors like Studio One and even more recent Bitwig have really found footing in this crowded market, but I think that's primarily because a lot of the standard DAW's were resting on their laurels and not innovating.
Pro Tools, Logic and Cubase aren't going anywhere. They are too entrenched, and too many people are reliant on them. So that leaves the table scraps for everyone else.
The only thing that will keep the others going is trying to appeal to a broader audience and ensuring a healthy economic environment to produce future editions.
I do think Studio One has kind of gained ground as the home musicians recording app. It's relative ease of use and drag and drop features are very appealing, and the fact that it can rely on Pre Sonus hardware to offset it from having to be profitable by itself. It does severely lag behind competitors in certain areas, but their development cycles have been able to provide just enough to keep users engaged, and at the same time provided for a maintainable ecosystem and kept development costs in check.
Bitwig is a very interesting one. I think they will mainly be a pain in Ableton's side for years to come, but they have thought outside the box a bit, and if they can continue to keep development costs low, and engage their already loyal fanbase, they should be able to keep going.
But the reality is, that anyone not named Pro Tools, Cubase or Logic, is potentially vulnerable. Doesn't mean they are doomed, because nobody right now is going to unseat those three. But it does mean staying profitable and staying competitive is a must.