Lack of software. Or at least lack of high-quality software for getting real work done. I had an Android tablet for a while. It was nicely portable, had good battery life, could do a lot of things well, but I just couldn't find any apps I liked for two things I do often: ssh and creating presentations. One ssh app could do tunnels, but got all confused if I tried to open multiple terminal sessions. Another handled multiple sessions OK, but couldn't do tunnels. Then the two would interfere with one another if I tried to run both simultaneously. For presentations, many couldn't do something as basic as keep track of where my cursor was, and would add text at the wrong place. Others at least worked, but couldn't do anything more complex than a bullet list. A real email app would have been nice, but I had to use both home and work webmail (which are very different) instead. From what I can tell, all of this has only gotten a tiny bit better in the last couple of years. It would be great if there were more Android developers coming from the desktop space instead of the phone space, producing more desktop-like apps, but that doesn't seem to be the case. As long as that continues to be the case, using Android on one's primary machine will continue to be frustrating.
ChromeOS, on the other hand, seems to be in better shape. I'm seriously debating with myself about whether to get a regular Pixel (not Pixel C) as my next main computer.
ChromeOS needs a good general mail client as well, there's been some work in this space, but from what I've seen it's still not there yet. I actually like GMail for general email... though account switching with more than 2-3 accounts is a pain.
Yes, obviously it's a chicken and egg problem. Once they sell 100,000,000 "desktop" devices that'll change. The reason Microsoft Windows destroyed everyone else was because you couldn't get quality software for most other computers. Windows Phone can't gain traction because it lacks quality software, for example. The problem is that software rarely comes first.
In short, if enough people overlook Android's shortcomings, it'll eventually reach a tipping point.
Can't speak for GP, but it's an embarassment that in 2015, Android still doesn't have built-in multi-window support. For crying out loud, even Apple beat Google to this, and they're typically behind when it comes to these things.
