I suppose you could say it started 30 years ago, but it really accelerated exponentially with Trump's presidency, the MAGA movement, Covid, the election denial, and the rise of social media.
It’s been 30 years of crisis that’s done a mental job on the US population. From the first Iraq war to now, war, Y2K, terrorism, war, housing bubble, Covid, and high inflation, all while sprinkled throughout with mass shootings at schools, concerts, work and various other (attempted) killings of political figures. Couple all that with stagnant wages, a culture of greed, profits over people, compromise is a dirty word, red vs blue, ridiculous housing/rent/healthcare costs and it’s no wonder we are where we are. People have checked out and that only exacerbates the problem even more.
Of course that’s not even mentioning the media, internet, foreign propaganda, and faux grass roots entities highjacking people’s legitimate concerns.
History will look on these times as the return of the dark ages.