Not sure how serious your suggestion is, but one quick answer is that a lot of the factory farms are owned by billionaires and publicly traded ag conglomerates who are making good money and wouldn't just need the capital back, they'd need an investment that gave the same steady returns.

Seems like a good plan, but the problem is that the available land is scarce and we only have one planet.

So we'll have to choice either to undig (and uncontaminate) the fertile lands under the roads and streets in the urban areas, that is a way;

or instead burn the last forests and give our precious natural areas to the pigs, literally. The pressure to ocuppy still relatively intact areas and the last protected sanctuaries for biodiversity would be irresistible and inescapable.

And is a wrong (but much repeated) idea than we'll stop the suffering. Is just that they are conveniently dismissing the suffering caused to the ecosystems. "Gazillions" of savage animals, plants, trees and fungi will suffer inmensely if we scalate the solution to all our cattle.

Couldn't the old owners just open new factory farms and outcompete the now-free range ones by being cheaper?

Well can't the same argument be made for cutting costs in prisons and working inmates to the hilt?

A better answer is hiding in your posts. It's that: We believe that humans, even criminals, have dignity and should be treated decently despite their wrongdoings. The argument, then, is that we could extend that "deserving of decent treatment" to animals.

It doesn't need a billionaire to make this happen (which is why you're confusing me), it just needs culture to change.

My question I guess is this:

Does unregulated Capitalism have the mechanisms to abolish such things with time? If there remain even 10% of meat eaters who want to pay $1 for a hamburger, who can stop the factory farms??

The only thing I can think of is a billionaire buying all the animals the way slaves were redeemed for money in some countries. After that no competing farms could start because they wouldn't have the animals to start with.

Of course. That's why you need regulations, not billionaires, in both cases.

So can advocates of capitalism admit that it needs to be regulated? How would factory farms have been abolished under anarcho capitalism? How would child labor or sweatshops be abolished? They say that under the NAP there would be no coersion, but clearly there is.

They say private ownership of animals will prevent their extinction, like commercial bees. That may be true but what about their welfare?