It's not happened over the past few years, but the past many years.
It's boiling frogs. You can't throw a frog into boiling water - he'll jump out. You have to put a frog in room temp water and the slowly bring it to a boil.
But no, we're not all morally bankrupt, just our war monger corporate government - that's what is morally bankrupt.
The entire whole of American mass media - that's a completely morally bankrupt coterie there too.
Believing what mass media proclaims as "true" makes individuals either morally bankrupt or so stupid that they're beyond the pale so far as morality any way - they don't understand the concept.
None of this has happened by mistake. America couldn't stay the way it was post WWII, there was too much corruption to be spread via bankers and media thugs across the globe for the common American to not become infected with that garbage too, of course.