Marketing for this particular product is irrelevant. Only cost matters. If it becomes cheap to mass produce, governments around the World will slowly start legislating [1] to either make meat from animals illegal to produce, or prohibitively expensive (through taxes) for the majority of people to buy. Meat from animals would become a luxury item.
If it's cheap and it tastes nice, most people wont care where it came from.
[1] Given the state of politics in the US, it would probably be incredibly difficult for such legislation to come into existence there. I suspect Europe would lead.
Long term, I agree, but the short and medium term can be heavily affected by marketing, and that can still add up to a lot of money/animals/pollution/etc. before the cost advantage wins out.
You don't need to raise taxes to kill the cattle industry just remove the gigantic subsidies and force it to compete with something that costs 1/3 as much.
If it's cheap and it tastes nice, most people wont care where it came from.
[1] Given the state of politics in the US, it would probably be incredibly difficult for such legislation to come into existence there. I suspect Europe would lead.