There would be the monopolies with private armies and more money than God to shut down new competition. They can lower prices for years to run at a loss locally to run the newcomer out of money, or just do a hostile takeover.
Yeah, so make it easier for competition. And give antitrust actual teeth. There's massive money flowing into the government and campaigns to turn it into the type of no regulations government you're proposing. So we need to fight really hard to actually enforce those regulations so monopolys don't form.
Yes regulations for smaller companies have been added. And big companies love that. Eli Lilly wants as many tests required as possible even though it costs them money, because they're better able to afford it than their potential competition.