They'd probably go extinct, what farmer in his right mind would want to take care of hundreds of cows that wont make any profit?
The only reason cows and other farm animals are alive is because we keep them alive for our sake, other than that they don't have any purpose really or not that much, they don't get fed on in the wild because they don't live there, they are only part of our food chain.
This probably sounds weird coming from a vegan, but animals cost money and when there is nothing to be gained from them in any form, nobody wants to have them.
So the only thing I can see people do is letting them die off.
Either way animal " exploitation" wont ever stop, because unfortunately we still depend on animals for way to many things and I don't see that ending any time soon, but people can help reduce it.