You're thinking with the mindset of a company that needs to save $50 so that it can make rent at the end of the month, and wasting valuable time and effort scrambling to scrounge up money.

Large companies looking to increase revenue can't operate like that. If they're going to penny pinch then that oversight alone to micromanage the expenses of the company with thousands of employees would probably cost more than the money it saves.

And not only that, lower the productivity of the entire company as everyone puts in weekly effort to justify every cent, instead of doing their actual work.

Management commits money for the budget it invests into the company and as far as they're concerned, it's spent.

They don't care about penny pinching to get back $500k of their $500 million budget. They're more concerned on whether spending that $500k could have raised their revenue by another $100 million and the only way to know is to spend it. A healthy company drives forward to maximize revenue, not look backwards to save a few cents.