IMHO, one of the biggest reasons Trump was able to win in 2016, and lose by a narrower margin than expected last year, was because U.S. public trust and faith in mainstream media has cratered to an all-time low.
Long gone are the days of Walter Cronkite. The lack of faith in mainstream media drove millions of Americans to Parler, social media, Fox (which up until recently was firmly in the Trump camp,) etc. which then allowed echo chambers to sprout and persist. The notion that “the mainstream media is lying to us, and they’re biased” increasingly gained a firm foothold, and fanned the flames of QAnon and Trump’s support.
Despite Biden’s win, the Democrats are looking at facing Trump 2.0, Trump 3.0 opponents in the years ahead - and perhaps, in fact, maybe even losing again to a like-Trump-but-savvier candidate in 2024 or 2028 if the public doesn’t regain faith in the media again.