The problem isn't that math isn't important. The problem is that the math being taught isn't important.
With calculators and computers, nobody needs to know math itself.
Totally disagree. There's definitely a base level of mathematical understanding that is necessary to use calculators and computers. For example, students need to know that entering "1 + 3 / 4 - 2" into the calculator is not the same as "(1 + 3)/(4 - 2)".
Personally, I think computational mathematics is one of the important areas where the "traditional curriculum" is currently lacking. It's like the curriculum is trapped in the early 1900s and hasn't acknowledged the way computers have transformed society. In this technology rich era, students need to become educated computer users.
Accordingly, the focus of mathematics education needs to shift from "memorizing formulas" to "thinking algorithmically". Not only will this benefit the students going into further STEM studies, but other subject areas as well. Even something as simple as "baking a cake" can be thought of as an algorithm.
Is there even a market, let alone a convention, for selling game concepts?
Nope. Quite frankly, the only way its going to get made is if you do it yourself. I'd suggest using an established engine to cut development time/cost to a minimum and going with a digital distribution service like Steam to bring the product to market.