This question was raised in my post of July 25th: If variable scopes are so terrific, how come hunters like Jack O’Connor didn’t use them, preferring straight 4Xs and the like? The answer is that Saint Jack began hunting just about at the time that scope sights became practical for use on hunting rifles, and his career ended at just about the time that variable scopes became reliable enough that you could rely on them, sort of. Early scopes were enough of a nightmare without the added complication of power selection. But once variable magnification became practical, it converted even the old-timers. Warren Page, who did the bulk of his hunting in the 40s, 50s, and 60s, was a fixed power shooter for all of that time, but by the early 70s, he was using a 2X-7X.
Scope optics have improved so much in the past 20 years that there is no comparison with what went before. Lens coatings are far tougher than they used to be and transmit far more light. Where things really have not progressed much is in scope machinery. There is no shortage of fragile adjustments, adjustments with vague, mushy clicks, adjustments that don’t repeat reliably, adjustments that flat-out break, and crosshairs that detach from their moorings.