It’s shame Mozilla gimped Servo by shackling it to Gecko for political reasons and giving it utterly stupid priorities like VR. Some of the ideas put forward were great. It was really inspiring to see that such a cool R&D project was possible in a space as uncompetitive as web browsers.
If its any consolation Mozilla will never threaten the browser engine that is used by the company that provides the lion's share of its income, just saying.
Technically Mozilla incomes come from being a foil to Google for an hypothetical antitrust probe. At this point both Gecko and Firefox are utterly irrelevant.