Also, F&TF/Cruis'n, as I said above, plays pretty much identically to Cruis'n USA. By the mid '00s people wanted more from a racing game, further hurting it once it got a home console port. Cruis'n for Wii has no additional features worth mentioning, unfortunately; in that respect it's a big step back from Cruis'n World or Exotica on the N64, games that do add a fair amount of new stuff. It also released years after the arcade game and was very harshly (and somewhat unfairly, considering its '04 original release date) bashed online for its bad graphics. So yeah, of COURSE it sold worse than Daytona USA, it'd be very shocking if it didn't! I remember all those threads on NeoGAF and the like bashing Cruis'n again and again for its bad graphics, that "Car Vault" picture, etc.
The decline of arcade ports may be a factor as well. It's noteworthy that there have been very, VERY few home ports of arcade racing games since, particularly Western ones. Raw Thrills, the company which made F&TF and that was founde by Eugene Jarvis, the creator of Defender, Robotron 2084, Cruis'n USA, etc, has published ten, yes, ten racing games after the first F&TF, which released in arcades in 2004. Not one has been ported to any other platform, not even the fairly prominent and high-quality H2 Overdrive, the new boat racing game from the original creators of Hydro Thunder.
http://en.wikipedia.org/wiki/Raw_Thrills F&TF is the one and only racing game on that list to get a home port. And none of their light-gun games have gotten a home port since the Wii port of Target Terror (another '04 game and Raw Thrills' first release), either.