start controlling ticket price. you can create more revenues than the AI will... this will help the budget rise as you make more the previous year.
a good tip in successful windows of time: unless things changed: bump season ticket price to 1.5x or even 2x your normal end of year ticket price that ~fills the stadium or maximizes profit (not necesarily the same thing value). bump it back down for reg season price.. BUT, as you win more games start testing the waters for increasing ticket price as the season goes and maintain same attendance.
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ignoring any distribution %. of gate revenue... so consider that after the basics are understood, or like me i turn that sharing off
e.g. lets say i am getting 42k / 45k @ $30 regular season ticket price the first month (excludes opening day and weekd vs weekend are 2 different values to reach same attendance, fwiw - ignoring weekend vs weekday to save time/effort in example)
at some point you see a shift in attendance.. all of a sudden you see 44k or SRO @ $30, not related to weekday vs weekend. as long as you don't got on a long losing streak, you can likely bump up ticket prices and make more money per game - even if attendance drops back to ~42k/45k as it was before..
use the shift in resulting attendance to detarmine when you can bump up the price and maintain #'s in the seats.. = more revenue. you will start to be able to predict when you can do this and after how many wins+games you have in season. more success = faster increase over the year and a higher ceiling that you can attain.
a bumpy year in w/l column? probably can't increase tickets or if you do, may need to dropthem back down if you start to lose too much. it will be a function of sucess and how far into season you are.
you will earn more if you start out fast and build up that 'fervor' than having a 20gam win streak at the end to barely make the playoffs. financially speakingn you can earn more if that 20game win streak happens earlier in the year in OotP.
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i bet you can increase it by 20-30M above and beyond what hte AI can get in yearly revenue, if you optimize all revenue streams. i guess that's just season ticket prices and reg season prices, lol. the rest is out of your control -- like media contracts and merch revenue. that's solely about market size and success if it isn't constant (nat'l media contract is constant in default).
size of stadium will matter.. e.g. a 54k stadium and a ~.600 winpct should be able to make ~$140+M gate revenue or more. that's only ~$32 average ticket price... (use calculus to determin optimal price for season ticket.. hint: it's WAY higher than what you charge in april)
you can see the max local media money you can get buy editing team interest etc.. then checking future contracts on accounting... it can sway due to success, but not a huge amount.. especially for a smaller market. try to remember min/max values for your local media contract and gauge how well you expect to do for future values of that contract when it expires.
like matt said, you've just kinda hit the ceiling with ai control and your market size.