Houston — Why not Houston — There are two major airports, IAH (Bush) and Hobby. and a ton a flat Texas land to pave and install off airport parking. Whereas Park n Fly was the only off airport location 30 years ago — now they have mucho competition, and they, and the other off airport locations are using every marketing idea at their disposal to attract new customers. Read about it here.
Of course, parking is big numbers for the on airport operations. They use the more than $62MM collected at Hobby and IAH for all sorts of projects on the airport. They are feeling the competition and are starting marketing campaigns of their own.
Off airport locations use price as a big attraction, however service is important, too. Note the comments by locals indicating they are willing to pay a bit more for better service. Off airport can give that service with valet, concierge, and more frequent vans. There is nothing more frustrating to see four vans from the competition go by before the one to take you to your car arrives. Frankly, that is what I use to decide where I am going to park.
And the beat goes on.