I think the historical perspective can be misleading to a point because in the past(70s in my case) stuff weighed less, and people would do weird stuff like walk.

On the weight thing, think of oversized tubes, corduras, sleeping bags vs. a blanket or using hostels only; down vs. polarguard, etc... They carried a lot less toys, no expresso makers, loungers, cell phones, locks, and on and on through the endless list. Most people weren't fat. Apparently the steel wheels were an advantage on the uphills, though I guess not if they were pushing...

My mom and dad toured back in the forties, he toured on a single speed she had an English "racing bike" with a 3 speed hub gear, and drops. It was still around when I was a kid. People in Ireland even in the 70s could often be seen pushing their bikes up long hills. Normally when one came across a local cyclist they were walking, since in a given day one spends a lot more time walking up hills than tearing down them.

Also, to add to BB's point. It isn't just about the 5 more gears down, it is also about the narrower spacings (if you so choose) that will allow you to spin at optimal levels over a larger percentage of a trip. My own recipe for touring gears is a low gear, and as many usable in-between gears as possible, and not much in the top end. That is what you will use out touring, though you may prefer more top end when testing the bike, and riding unloaded in general. On the road, unless I have a grade or a tail wind, I don't use the large chainring much at all. Without a load on the road I hardly use the small chainring.