Junk Science is the Think Tank's raison d'etre
If you got away with JUNK SCIENCE before 1945 - and many academics did because rigorous peer-review before publication was not actually all that common back then - increasingly you couldn't so after 1945.
Second rate and lazy scientists and academics who couldn't cut the mustard, cut classes - bailed out of academic life after they had established a few credentials and swam - like rats - to the rising ships of the anti-peer-review-oriented think tanks.
The post-1945 rise of the think tanks were also industry's and the wealthiest families's response to that fact it was getting harder and harder to find real university professors willing to be their denier-liars for hire.
The two trends met in the middle : both needed each other.
Think tanks thus do serve an useful role for society after all ; providing the first rate sort of home for the second rate sort of scholar....