The strong point of this sim is tires that like to slide. The most popular and numerous type of circuit in America, by far, is the dirt oval. They're everywhere! Dirt racing used to be the ladder system for IndyCar. A "Racin' USA" set of DLC would be incomplete without these. What's more, most of these tracks are well under a half a mile, so several could be made in the time it would take to build a regular circuit. That, combined with the fact that these little venues aren't going to charge anywhere near what a Daytona or Watkins Glen would for licensing, means much cheaper development. The cars themselves would also be a lot cheaper to license.
I would also like to mention that the 410 sprints in the video above have a higher power-to-weight ratio than F1 cars. 950 HP and 1425 lbs.
In the recent Facebook Q&A, Renato answered a question regarding Tykki dirt track from AMS1: (my emphasis)
