Because this is what naturally happens. The more you try to bend economic reality by forcing people to do less optimal things, the more the economy starts to resemble Soviet Union - i come from there and i don't want to go back. I agree, it is sometimes necessary, but it should be approached with great care, to do only when indeed absolutely necessary.
In a free market it WILL be, regardless of must or not.
You can debate if a business has cultural value beyond that (and I think they do) but that's not the reality of today.
I don't think that follows at all. If a business is on the area and successful, it doesn't necessarily mean that it is the most successful business that could be there.