Even if veganism caused diminishing meat demand around the world (it does not, see other comment), I see no reason why artificial meat research would be impeded

Even if veganism caused diminishing meat demand around the world (it does not, see other comment), I see no reason why artificial meat research would be impeded. The meat industry will try to optimize their production cost, no matter what. Your line of thought would make sense if meat production was artificially limited and exponentially more expensive (because of environmental restrictions or farmland price, for example). Instead the opposite is happening. Meat's never been cheaper.