There aren't "plenty of other rental car companies out there". It's an oligopoly. There are only three: Enterprise also owns National and Alamo. Avis also own

There aren't "plenty of other rental car companies out there". It's an oligopoly. There are only three: Enterprise also owns National and Alamo. Avis also owns Budget, Payless, and Zipcar. Hertz also owns Dollar and Thrifty.