$500K is like 1 or 2 fully loaded engineer salaries in the US. It’s not all that expensive.

They usually don't make sense optimizing before achieving these levels of expenses. I mean, for a really long time the expenses are so low that it would cost more to engineer these solutions in the first place, and then they suddenly run through the roof exponentially.

But mainly, priorities and "it's not that much in comparison to all else". And perhaps not even tracking the costs properly :)