i understand but disagree with this narrative.
all-rounders always crushed the climbers in TTs. Merckx, Hinault, Indurain, Anquetil -- the riders with the most TDFs all crushed their opponents in TTs and largely "resisted" in the mountains.
the problem with today's routes is that instead of being happy with 2-4 possible GC winners, the designers believe that they need to have 10-15. so riders like landa, pinot, gaudu, mas etc... have been made to seem like GCers at some point in their career when really they are not.
you need only two evenly matched all-arounders to make a stage race exciting: Merckx vs. Ocana, Merckx vs. Thevenet, Hinault vs. Lemond, Hinault vs. Fignon. Lemond vs. Fignon. Pog vs. Rog. Pog vs. Vingo. Rog vs. Remco.
it is in trying to superficially create more contenders that route designers have diluted the test of stage racing.