I always say, that finance departments can easily calculate costs. But opportunity costs most of the time don't make it into the books.

Why do you assume it is finance departments making these decisions?

Finance departments get hit with the same clueless 'cost saving' as everyone else! Often because the savings are so 'obvious' to MBA wielding middle managers, the decisions are made without Finance advice.

It is also often just a corporate politics thing. Your department has to save money, but there is no measure of how much money you cost other departments. In my experience this is more often done to Finance than by them. Pushing more work from frontline departments to back office departments sounds great to an Ops manager, and this frontline departments often contain people who are good at selling their idea.