The real change is going to happen when people can't tell a difference in taste and Walmart starts selling synthetic meat at a substantial discount to meat. At that point the consumer won't care just like the consumer doesn't care if their strawberry flavored cereal has real strawberries in it.
Strawberry flavoured cereal and synthetic meats are miles apart - if we're talking lab grown meat that's amazing - it's tender meat that has no ethical issues. If you're talking the impossible burger, that's a burger that again has no ethical issues and a minor compromise in taste. Nutritionally it's basically equivalent to a normal burger. Strawberry flavoured cereal is nothing like a strawberry, and can't possibly…
My guess is that beyond will soon be cheaper than regular meat, but that the requirements for creating lab grown are simply going to be too great to be able to compete economically or ecologically. I'm going to be very happy to be proven wrong someday, but that's my initial, knee-jerk reaction.