I wouldn't count them off that easily. Valve is making their own autonomous headset, should be out next year. It will be more expensive, yes. But it will be faster and it will be full blown Linux PC with access to whole library of PC games. Might be very competitive(still will lag in units sold though, but mostly due to supply constraints). Any you shouldn't forget that Sony is still on the market(autonomous PSVR is not out of the question) and Apple is making their own headset.