Not to get into a business analysis, or debate here, but no, money is tight with Disney....wait, don't write your reply back yet, read my entire comment
The amount of money that they have to show investors is real money, however it is money that is effectively "spent" and must be accounted for in that way. Certainly there is some wiggle room in the budget for some things, but just because they cleared $x billions in profit last quarter/year, doesn't mean that they can go and spent that money all up. In the next period they have to show various things to their investors, and if they do have a large project, then certainly they can say that profit is down due to a billion being spent on star wars land, and they will likely get away with it, but they can't say "We are down 10% in profit because we are doing a bunch of maintenance projects" I would love it if they could, but they simply can't, they would get destroyed. So yes, they could spend a little extra money, most likely it would get taken from another budget line, because another wall street metric that gets watched closely is total operating expenses. They also could and might have done this a few times, sneak up the budget for certain areas during a time when a new area opens, then dismissed the increased operating expenses as being related to the new area.... thus creating a new normal operating expense level.
You see, it is definitely not as simple as we wish it were.