Regulations also can stop a big business from taking over all the little ones. Regulations stop a business from simply poring it's waste into a river.
I would be hard pressed to think of a single example, where regulations prevented big business from driving out small business in the long term. In short term, for political show, you might see that. But over the long view, no.
Give me an example?
Regulation is invariably created (or twisted after the fact) to favor the vested interests in a given market.