"Each progressively more lofted wood would also be 1 inch shorter -- something the manufacturers don't necessarily do anymore either."

Right. I see about a 1/2" shaft length difference between the odd numbers on modern fairway woods. This could be another reason why the 3* gaps are seeming less effective.

For example, almost every length on this spec sheet only reflects 1/2" delta between any two odd number clubs in a subject model.

Adams Golf FW Specs