> It is quite likely that we can feed 7bn people.

We could probably feed a lot more, if we crammed everyone into small cages and fed them like factory farmed animals.

The question is why you would want so many people living like that? You are already indirectly pointing out that meat will be off the menu for future generations and I am sure there will many other things that will need to be sacrificed as the population increases (for example, fish populations don't sound like they are keeping up with demand). And at some point there are going to be some hard limits on how many people can be fed.