I'm on mobile or I'd go find a source, but I'm fairly certain some key people left before all that went down.
Not that maintaining a web browser is easy, but they WERE doing it, to varying success.
Does that really matter much, if it's open source? A lot of software converges on one or a few standard libraries or applications.
There is another cost that people don't talk about as much, and that is the cost to understand a large, alien codebase enough to be able to understand and change it. If the effort to contribute is too high, you can't get a second group of programmers to rally around the fork, and the new project will fizzle.
As an example, Google understands the economics of code very well. They know that there is little threat to market dominance for them to release Android or Chromium as open source.
I'm worried about that as well, but it's not really fair to attribute blame to most people at Opera, especially prior to the China thing. Things were okay there for a long time before that.
No, it's not.
> if Mozilla ever tanks, we could have a complete WebKit browser monoculture
Not a risk. Chrome dominates, and it uses Blink, not WebKit. (Yes, the distinction matters, and no, it is not a distinction that is minor/negligible/insubstantial.)