Why are all companies allowed access to your credit report? What can be done to limit access?

In todays world it seems as long as you pose as a business you can access information on anyone you want. I know credit reporting agencies say that this doesn't affect your ratings, but it seems like it does. Any business can see your report and credit scores, but you can't see your own without paying. Why is that?

First, businesses don't have access to your credit file unless you give them permission.

Second, businesses pay to see your credit report; you get a copy for free every year.

Third, credit bureaus are in another business that screens pre-approved offers and mailing lists, without actually giving out your information. You can contact th bureaus an opt out of these screenings.