Comparisons are always a bit tricky, both between generations and within a generation, and it is important to compare like with like.
As a generalisation climbers have always been smaller and lighter than cobbled classics riders and that is still the case. Any exceptions ptove the rule:-)
Tour de France winners in the early days were ultre endurance riders with arguably more in common with say Mark Beaumont than Chris Froome. In the modern three week stage race era they have by and large been all rounders, albeit excellent all rounders but strong climbers, strong time trialists, in fact just strong.
Modern equipment makes a difference In terms of body shape but let’s not forget that easier gears have let to climbs becoming more extreme, and I suspect that changes/ advances in nutrition have also had a real impact especially in terms of power to weight.