There's something to be said about time investment. You're suggesting that tinkering takes time. If I want to keep current on all the math I learned in school, I'd have to invest a significant amount of time in addition to the time I already invest in keeping up-to-date with languages/frameworks/platforms/algorithms/datastructures/databases/etc.
How often would I use this level of math? I know I use the others on an almost daily basis. Coming up with something I need linear algebra for, though? Few and very far between. Maybe you use linear algebra often, but most of us don't have a need for it.
And if you disagree, then I think you should actually know abstract algebra, number theory, topology, etc., so that when the next problem comes along, you can 'quickly come up with an optimal solution'.