Through franchise fees, fighting public right of way sharing, and other forms of lobbying these large corporations have used law and regulation to their favor. This is not a position libertarians support and it is not a market anyone would point at and call "unregulated" in any sense of the term.
So your choice is: big business squelching competition directly or big business squelching competition through lobbying.
The problem still goes back to unchecked unregulated big businesses forcing themselves on the country with their market share and giant wealth.
Yes. Most regulation benefits some corporations, because there are very few regulatory issues where there aren't corporations on all sides of the issue.
> (regulation tends to mean "regulation against corporations")
No, it doesn't. There is certainly a particular faction that sees regulation as inherently "anti-business", and a popular association of business = corporation, so I can see how that idea would come about, but its not at all what regulation means.