Actually no, this goes back to corporate budgeting.
Corporate budgets for things like maintenance is done a year in advance. What happens is division heads ask all their middle managers, hey give me your budget for Fiscal Year 2019. They give their budget requirements, and are allotted that amount of money. They now have only that amount of money to use for a whole year. Sure they have a list of projects they'd like to get to, but they have priority projects that require x amount of money. Say for example during the Splash refurb they encounter extra dry rot and costs more than the budget accounted for. Well that money has to come from somewhere, and asking Daddy Chapek and Uncle Iger for more money doesn't work. So they have to take that money from other projects which were slated to get funds. Now that project just went lower on the list. So now they have to try account for it in next years budget. And you see how the rest goes.
Its corporate budgeting, and its something most Disney fans don't realize. Most think, like you, well Disney makes hand over fist profit, just throw more money at it. Well there are rules to these type of things.