Some execs at Mozilla think MR is the wave of the future. I think it's mostly a party trick with a very niche market and will always only be a niche market, and wasting top talent on MR seriously detracts from a project that is a hundred-fold more important. But maybe that's just me.
I have mixed feeling about this. I’m inclined to agree with you however if it did take off it could mean the difference between Firefox dying and becoming the market leader.
VR seems like a huge waste of resources though. Yes I think it will take off in the next 10 years, but are people really going to be using VR to browse the web? And can you really make good VR apps in JavaScript? I doubt it.
People still don't use WebGL/WASM for traditional 3D games which are less demanding.
You could've asked something similar 12 years ago: sure, smartphones will probably take off, but are people really going to be using those small devices to browse the web?
Mozilla missed that boat; they can't afford to miss this one if it's going to take off. Weighing that against investing resources now, at a time when they're financially healthy, makes it a pretty sane direction in my view.
I don't think that VR sets have the exponential growth that smartphones had on their first years. So this new target of Mozilla may never expand outside a niche market. And I'm afraid their flagship browser could suffer from the side-effects of this focus.