Meat is a big industry. Millions of dollars of meat are sold hourly worldwide. Meat costs more than vegetables, and there is a big environmental cost too.
So a big drive in biology right now is to grow meat in a test tube. This could automate the feeding and waste elimination, and the meat would never be aware of its state. There would be fewer waste issues, less loss to disease, it would cost less. One big problem:
Cells live upon an extracellular matrix of carbohydrates and proteins. Outside an animal, cells tend to fill one layer, and then stop growing. Only cancerous cells can grow arbitrarily large, and no one wants to eat cancer-burgers. (Except me, and I'm only debatably sane. I also wanted to eat artificial food, which most people would find abhorrent.)
It is possible to grow many single layers and grind them into burger, but I think people will be the most satisfied if an artificial matrix can be developed. This way it could grow entire steaks and chops. We'd need a new matrix for each one. This makes it more expensive than traditional animal rearing, until it gets automated.
Whether this counts as vegetarian or vegan is debatable. Cells can be extracted without harming an animal, which is the traditional objection to meat-eating. It still has an animal origin, which would freak out most existing vegans.
I look forward to cheap steaks cloned from a cow's cheek cells.