"NINETY YEAR RULE" between epochs cum generations : ideas don't change, merely die out

   If Romanticism was born in the heady atmosphere of the 1790s, its replacement by Scientism in the 1870s might have no more significance than Scientism's replacement, in turn, in the 1960s : all were victims of the "Ninety Year Rule" .

   All of these replacements weren't the result of the intellectual triumph of exciting new ideas, but merely the fact that the last of the powerful men holding older, once-exciting, ideas had finally died.
   Depressing, because we may not have the luxury - this time - of waiting till the last of the Modernist/Scientism Limit-Deniers finally dies out some time in the 2030s...