By growing just muscle and fat cells it ought to be possible to create meat without the moral downsides of raising and killing full animals. This isn't commercially practical yet, but further research might be able to get it to where it was the cheapest way to produce meat. For people who think animal suffering is very important, is helping this research along one of the most important things to do?

Let's just assume for now that we can get the cost of lab-grown meat below traditionally raised meat, and that people get over their initial negative reaction to "artificial frankenmeat." What happens? How do people react? What do they eat?

If we could create meat that tasted exactly like existing meat cuts, completely interchangeably, like beef produced in one country instead of another, I would expect nearly everyone to switch and switch fully. Why pay more for chicken raised and killed on a factory farm? But there would probably be taste differences, ways in which it tastes better, ways in which it tastes worse, situations in which one or the other is better suited. Just as people eat many different kinds of meat, I would expect the majority of people without strong moral feelings on eating animals to end up eating lab-grown meat where it's better and live-grown in other cases. One doesn't even have to be 'better' for this to work: people's simple preferences for variety might be enough to keep both up as options.

The closest analogy here would probably be plant-based fats and artificial sweeteners. Many cases where we used to use lard, butter, or sugar we now use substitutes, especially in commercial cooking. But because they don't taste the same we don't just use whichever's cheaper, we use what works in that situation. It's not a perfect analogy because the difference in chemical composition means taste is definitely not all of what goes into the choice. On the other hand these tend to be supplemental ingredients instead of the focus of the dish, which means the force of variety could be weaker.

Overall I would expect cheap lab-grown meat to reduce factory farming some, but come nowhere near eliminating it. It would probably do best in processed food where people can work hard to take advantage of its strengths while stepping around its weaknesses and the manufacturers are very price conscious. It might also make it politically easier to ban factory farming because you're asking people to give up less. On its own, though, I don't think it would make factory farming economically impractical by simple price competition.