Large corporations could stop crushing smaller businesses if antitrust law was expanded. Antitrust law limits the ability of corporations to form monopolies. Monopolies in economics are able to destroy the competitive market and small businesses by undercutting product prices and driving smaller businesses out of the market. If Antitrust laws were expanded small business would have a better chance of surviving in a market where there are large corporations to compete with.
If large corporations were actually concerned about smaller businesses they wouldn't be putting them out of business, however that is what capitalism gets a country. We've let the cable companies merge and join together and monopolize areas for far too long, but we've also let corporations like Wal-Mart squeeze all the life out of our economy as well. If antitrust laws were expanded it could help with these issues, however politicians would have to pass these bills against the will of those who tend to fund their political campaigns. How likely do you think that is?
No, large corporations could not stop crushing smaller business if antitrust laws were expanded, because there really aren't that many modern examples of large corporations crushing smaller businesses. The days of price gouging in a certain location are over, with the advent of the internet. Consumers really don't need to worry about anti trust anymore.
Even if antitrust laws were to pass, it would not stop large corporations from crushing smaller businesses. I think that the antitrust laws will not stop larger businesses from decimating smaller corporations. I also do not think that it is the purpose of the law to do that in terms of policy.