It's slightly more subtle than that. The budgetary control management system that companies like this use isn't primarily designed to limit spending to the min

It's slightly more subtle than that. The budgetary control management system that companies like this use isn't primarily designed to limit spending to the minimum necessary. Its primary purpose is to prevent any political power being built away from the management office, by constraining access to the critical resource. I mean this literally and historically. Budgets being used for management control dates from when the CEO of General Motors couldn't control the sprawling divisions they'd bought, so he (well, his CFO) brought in budgetary controls invented by McKinsey (the man, not the company) so they couldn't move without his say-so. And of course because it worked for GM, it must be good for everyone.