You can also run into the opposite problem, where they license a commercial version of a dependency, and instead of paying ten grand or whatever, they pay a senior (way over six figures) to re-implement the same functionality, which wont be maintained anywhere as well, and it takes them over a year to reach parity. Totally never happened anywhere I worked.

It astounds me that companies would rather waste hundreds of thousands of dollars instead of just throwing a few thousand that will benefit them in the long haul.

I genuinely believe more companies should adopt a policy of just letting devs work half a day on fridays on whatever they want, whether it be technical debt, or even open source projects the company depends on. Maybe that would be more feasible, but even then lots of places would still not understand the value.