The game is plagued with non-participating managers who entered one or two races and then abandoned it. As I understand, because of it even fairly mature league are underpopulated as such managers are eventually removed. E.g. in my league (est. Nov 2019, races every day, so it should be around season 8 I guess) there are only 8 and 11 managers in Pro and Elite, in Pro almost everyone seems to be inactive. Meanwhile, I joined midseason and will likely not reach place 2 in Rookie because there are two more-or-less active managers.
Suggestion: limit number of promotion places (2, 3, 4) not based on the season, but instead on number of free places in the upper division at the start of the season. E.g. something like 0, 1 free places - 2 promotions, 2-5 free places - 3 promotions, else 4 promotions. Relegations could use a similar logic, but based on the number of free places in this division. Though this is probably less important, because relegated teams are inactive in 99% of cases anyway.
As it stands, I feel I'll give up on the game again if I'm not promoted this season, because there is zero interest in "winning" against a grid of bots.