People eventually did start seeing their bags yellow with age, and realized it might affect the comic inside. Again, not a problem for mylars, but those weren't cheap. So the solution some people opted for -- assuming they just didn't keep the old bags around indefinitely -- was to simply replace the bags every few years. I think I recall hearing it was recommended to switch your bags every 4-5 years.
Over the past few decades, I've replaced most all of my bags. But I do have one old issue that's still in the regular plastic bag I bought it in. It was one of the first Fantastic Four back issues I bought, and I picked it up at a kind of mini-convention that was in a local shopping mall. I think there were maybe half a dozen vendors and that's it. But the reason it stands out so firmly in my mind was the, as far as I know, unique marketing gimmick the shop had taken. They'd printed up their own custom bags...
In the past 30-some years, I have never seen another shop do this. Every comic you bought from Dragon's Lair came in a Dragon's Lair bag. This, I think, works better than a standard business card or flyer because not only do I have the shop's name and address, but I also know precisely which issue I bought from them. Even three decades later!
I don't know how pricey these bags were, or how many got thrown out as collectors moved to better quality materials, but it strikes me as a great piece of marketing for the time. Probably not as successful today, as the back issue market has largely fallen by the wayside in favor of trade collections, but it's a genius idea for 1984! Did any other shops ever try this?