My guess is that YouTube is the most common one. I know Vimeo is a huge platform as well.
I found some statistics from 2016. And It seems that youtube is by far the most popular one. And since it is not too hard to implement other players by using an HTMLviewer, why bother making a one-size-fits-all kind of control. It would be nice… though… but you can easily do it yourself.
These stats date from 2016. In 2017 things might be different. But the overall ranking is not likely to change much.