I felt this on 80s french shows too. Its as if 1h back then was longer than 1h now. It's super odd. People were probably happier deeply because all of the new spaces to play on, without much structure and productivity. Things were to be invented. Whereas today, TV shows are long term businesses who have to hold market shar, ensure the same thing every day. No time for stepping aside, laugh or listen.
Probably a difference in human and emotional education. Times were slightly rougher in the 60-80s.. people may have had thicker skin and more social skills.
All in all it might just be a natural cycle of sclerosis, not help by the internet amplifier.
ps YouTube suggested some letterman shows with meg parsont (a random employee working in front of the studio building) I felt Dave was a bit intrusive if not bullish on her. Made me feel conflicted, as I hold the dude and show very high in mind.