It's young, and even younger if you consider it's true "birth" to be when it gained feature parity with some other popular DAWs. Even if there were to be minor workflow improvements compared to the tools established people are already using, familiarity has a bigger impact on speed (and thus creative flow) for the most part. If you're an A-lister or studio owner, you already have an established workflow that has been proven to meet the demand of the work you have coming in, why change it when money is on the line? And when people are new to the game, the first thing they're gonna ask is "what do the pros use?" and emulate that, because well, how else are they going to decide when they don't know what they want?
Sometimes endorsements are just paid-for blurbs and/or videos from the companies themselves too, so I wouldn't take too much stock in to them. If you were comfortable with any old DAW, only with one of them a company would pay you money or give you free stuff to use? Of course you would pick that one!
If Presonus keeps going the way they have been with it so far, I'm sure you'll start to see it more often when the B and C-listers getting comfy with it now gain popularity down the line. I personally think Studio One will have no problem keeping steady in the long run, as Presonus is already making money elsewhere with hardware, so they're really in no rush to get more people on board with their software.
I feel like Bitwig is in a similar situation too. It really takes Ableton's "sound-design playground" aspect a step further. It's still missing some bits and pieces from Ableton though, and it doesn't necessarily give enough incentive to move when you already use and are comfortable with Ableton.
If you like it and it does things you need it to, use it!