That's damning with faint praise, isn't it? It can, at this point, do MOST of what an everyday Internet user might want? It's that whole 80/20 thing that everyone thought would let somebody overthrow Microsoft Office -- 80% of users only use 20% of the features. Well that's true and all, but it's not the same 20% for everyone, and you only have to miss one feature to make a Chromebook an untenable alternative to a Windows machine. There was a brief window where Chromebooks were significantly cheaper than a comparable Windows laptop but Intel took the ARM threat seriously, Microsoft took the licensing seriously and now the base Chromebook price from a name manufacturer isn't significantly cheaper than the HP Stream or what have you. "Most" is not going to cut it now that the price advantage is gone.
> There are lots of people who are content with its restrictions.
This is really only true in that we live on a planet with many, many lots of people, and so you can find lots of people for which almost anything holds true if you funnel it down. ChromeOS market share is a rounding error at this point, and if there were any signs that this was turning around, Google apparently decided they weren't enough for them to continue.