Things that Alton Towers do, and the subsequent budget have absolutely nothing to do with how the park performs, the park does not keep or recycle it's profits internally, they go to the parent company, publically traded Merlin Entertainments. This money is added to all the profit internationally from all Merlin operated attractions, and then each site will be allocated a budget. If Alton Towers perform poorly this year, the parent company will likely be considering a LARGER spending budget either for the latter part of this season, almost certainly for next season. To get bodies back through the gates and the park performing well again.
I really wouldn't be worried about anything anymore, the media are clutching at straws trying to find reasons to remind us of what happened, that is clearly backfiring, Scarefest will not be scaled back at all, all scare actors are hired and contracted in February so the only direction they will go with that is up. I know they are hired in Feb as when me and my wife had our recruitment afternoon they were being auditioned in the next room to us, the week before Feb half term.
When the parent company feel this has died down enough, expect a larger advertising campaign than usual and some form of special offer or event to draw people in.
We may even see a rushed new ride installed for next season to deflect people's attention and create an advertising campaign around.
As originally stated, don't worry about their budgets, they don't keep their or recycle their own money.