What Duck said.
And taking this one step further, back in the 1970s when I started doing this, there was no web and they DIDN'T have them in stores--other than medical supply stores where they wouldn't sell less than a case and the ones they had were thin and had no "baby" scent and were intended for your 90-year-old grandma.
If you wanted anything "baby like" you had to buy the largest toddler Pampers available and tape 2-3 of them together to make them "adult" sized, or wear cloth.
And for cloth? You either had to buy toddler sized cloth diapers and sew them into larger ones, or use towels.
And plastic pants? Again, you had to go to the medical supply store and get ones that snapped on the sides or else do the "trash bag" thing.
I only went to the medical supply store once. I bought a case of 80 "Disposable Adult Diapers" (that's what it said on the box). They were horrible. After using a few, I ended up just using the rest for pads to put under my butt when changing my cloth diapers.
And when buying those, the guy that worked there wanted my insurance information. Well, I was still on my parents' health insurance and DID NOT want to do this, knowing that they'd eventually get a statement in the mail that listed "one case of disposable adult diapers" on it.
So I refused, and then had to listen to the sales guy go on for about five minutes about "I just don't understand why you want to pay for these out of pocket when your insurance will cover them." It was bad enough being 19 and walking into the place to buy diapers WITHOUT all of that.
Anyway. Point is, even though we only have a few places to buy our stuff these days, that's WAY more than there were back then.