Mexican interventionists are now pushing the idea that Mexico is a country dominated by a free-market ideology which they call "neo-liberalism." But any serious look at Mexico's government makes it clear this is not the case.
The fruit of the Enlightenment has been the growth and centralization of the state, at the expense of all other institutions. The material plenty we enjoy today are in spite of this change, not because of it.
In a relatively unhampered market, a declining population is not necessarily an economic problem. But in a system where retirees can loot younger workers through government pension systems, there is a real problem, indeed.