Because miners producers do not have the same set of incentives that users consumers have and the bitcoin product exists to serve users consumers not miners producers, miners producers too exist to serve users consumers.
So...
Cryptocurrencies -- specifically the market for tx inclusion -- are the one and only special case where the laws of economics do not apply?
(As an aside, I'm quite sure that, when the producers shut off their alarm clock at oh-dark-thirty, and wearily drag themselves out of bed to face another long grim day of producing, that
doing it for the benefit of the exalted consumers ain't first and foremost on their minds)