I've done races like the bwr where it's mostly paved with dirt, races like grinduro where it's dirt the whole way, road only, races where it's singletrack that really should have been done with an mtb all on 1x. If I know I'm going to be on singletrack the whole way I'll pop on a small chainring, bigger ring for road, etc.
In the end 2x sucks when the stuff gets really rough which is why its pretty much extinct in cx. To say that a 1x can't be used for everything is silly. Unlike 1x you are basically stuck with a set of gearing all the time in 2x because the options available are tiny. Just because you are running 2x doesnt mean you can now take on everything either. Go try some singletrack on 2x and shift that front under some load.