I don't dare guess about a specific schedule, but I'd expect the end state to be meat that is safer, tastes better, and is less expensive.
Safer because it can be grown in sterile conditions, which greatly reduces the risk for contamination by pathogens.
Tastier because it can be more directly engineered for flavor, with fewer constraints. Take a look at how crazy things have to get in order to produce foods with the flavor and texture of veal or foie gras using current technology. Not having to worry about how you're treating an actual animal, or even having to do what it takes to keep the whole animal alive, isn't just going to improve those processes, it's going to open up a lot of other options as well.
Cheaper because it'll be infinitely easier to engineer waste out of the process.
"Grown in sterile conditions" and "cheaper" are two completely contradictory features.
Most agriculture is still done in the field, not indoors, because that's the most efficient way to do it. A large part of the inputs is "just there". Waste doesn't really happen in production, almost everything is put to some use. Real waste happens on the store shelves.
You really have to ask yourself, what are the inputs to the "lab grown" process and what are the requirements towards purity etc. It's an open question.
You are mixing up "waste material" with "material waste". The parent was making a point about cost. It's cheaper not to feed male baby chicks. It's cheaper to raze the forest. It's cheaper to let cows fart.
There are externalized costs to these things, but they don't really affect the prices that people are going to pay for the produce, at least not directly. I guess you can charge a small markup for being "green" (or pretending to be).
Now maybe a cow is only "3% efficient" in terms of calories, but the calories it takes in are really cheap and the calories it puts out are prized. It's a profit deal! In engineering, higher efficiency generally is more expensive and the economic optimum is never the efficiency optimum.
Most large-scale food processing, like baking, or sausage / bacon / ham production, or dairy production, is happily indoors. When you don't need to work with entire large organisms, like a cow or a corn plant, things become easier to turn into a factory environment.
Safer because it can be grown in sterile conditions, which greatly reduces the risk for contamination by pathogens.
Tastier because it can be more directly engineered for flavor, with fewer constraints. Take a look at how crazy things have to get in order to produce foods with the flavor and texture of veal or foie gras using current technology. Not having to worry about how you're treating an actual animal, or even having to do what it takes to keep the whole animal alive, isn't just going to improve those processes, it's going to open up a lot of other options as well.
Cheaper because it'll be infinitely easier to engineer waste out of the process.