You are correct that government regulation is used by politically-connected businesses to hobble their competition. There is a large literature on this. Tom DiLorenzo has done a lot of work in this area.
The Fed is a massive cartelization device for banks. Murray Rothbard has written about this:
Bigness of business, however, is a red herring. The real issue is whether an enterprise is efficient or inefficient. Private enterprise is constrained by profit and loss to serve consumers efficiently. Government intervention allows enterprises to receive profit and avoid loss while not economizing resources for consumers.