People whined about search licensing and it now seems there is a court order imminently about to kill those deals. That leaves either running other services or putting ads in the browser both of which attracted much complaining.
And no, forking is not the answer. Mozilla does the lion's share of security work and maintenance. If the mother ship dies the forks will slowly wither and die as they don't have the funding to replace Mozilla. If Mozilla can't make the numbers work a fragmented mess of forks will not do better. A few of these forks have made the problem worse for themselves by insisting on bringing back and maintaining the exploit ridden mess that was XUL based add ons.