Because Codemasters are rubbish and their F1 games have been crap
For real though they're a fairly small company (compared to other yearly sports game developers... EA...cough cough) and they think people won't be interested with this additional content in an F1 title so won't divert resource to developing it. Don't forget they get all your data from how long you play, what game modes, whether you actually set up the car, run practice sessions, AI difficulty...etc so they probably have the research to say that F2 isn't used that much.