Nixon still had Congressional support until shortly before articles of impeachment were sent to the House floor (late July 1974, and never voted on) which was 3 years after the Pentagon Papers were first published (June 1971). He was only forced to resign AFTER the media started covering the scandal and what it actually meant in depth and Congress was having to actually start answering questions from constituents.
There’s a reason propaganda-based “news” organizations like Fox News were created after Nixon, and regulations like the Fairness Doctrine were removed under Reagan. It was so they could control the media commentary and insert their own propaganda under the guise of impartial “news” services.
Organizations prior obviously had biases, but national news organizations were generally pretty balanced, nothing like many modern day organizations despite their clear lies about being balanced.