Honestly in my opinion, I don't think this would fix the issue but It would turn more players away from the game. For example if you spend hours in single player designing trucks that you want to use in an event for example but to then switch to multiplayer and loose that truck because the save is stored on the server. This would also mean that TMP would cost more to run as we would need separate server storage for everyone's save files and a whole staff base to deal with save issues.
People play the game for different reasons, some like to log in and spend 3 hours making a nice truck to add to their collection and others just want to drive with friends.
I like the idea of progressive rewards and external contracts, maybe or even make the fragile loads even more fragile but may the pay off so much more than what it currently is.