It's because the engineers are on staff and you're paying them anyway. Trying to justify a separate purchase, even if would be cheaper on paper, is way harder.
I don't mind, I'm learning something new. I suppose that in itself adds value to the company.
It would if the information got imbued back into the rest of the company, but it most often manifests as domain experts, who when they go away, someone else has to learn the thing all over again.