The median venture capitalist in the valley could outspend the US --- actually, probably the world --- on vulnerability acquisition. But there probably isn't an investor and there may not be a single tech company that outspends the USG on defensive security acquisitions.
I don't disagree on the lack of private hardening spending, which is really beside the point, because obviously there is very little incentive for a company when all they have to do is budget for useless CYA lifelock service.
Exploit development is a rounding error in that budget.
Is the money being spent wisely? Different question. But: nobody really knows how to effectively spend 100MM on hardening (a nice round number I picked at random).
You're redefining "hardening" to "hardening I agree with".