Mmx2 why can't I go any further without playing all these jam sessions

Does anyone on here play MX2 and why would not let you go to the expert unless you keep playing all these jam sessions it does not make sense to me

Thats the way the game works. Not much to do about it. Its designed to take you through all the features the game has to offer.
The 1000 jam runs can be done in as little as an hour. Start a run, wait three seconds, and repeat… 1000 times. It’ll be a boring hour, But put something nice on Netflix and Itll be over before you know it.