Dealzon editor Viet Do just unearthed boxes on boxes of old PC games. Why did he kept them through the years? Who the heck knows. Check out content in game boxes from the early 90s through the mid 2000s.
From 1991 to 2004
A few observations I'm able to make now as a 30-something vs. as a kid when receiving the games: game companies at the time really wanted you to register their product. (All those registeration cards!) Doing so made sense at the time, since registration provided an easy way for companies to build a outreach list.
You can tell towards the end of the boxes that registeration cards became less of a thing, as games moved more online and the Internet became much more of a norm.
2004's Dungeon & Dragons Online: Stormreach was the surprise of the bunch with tons of goodies in the box. Granted, Turbine was catering to a very specific bunch of gamers that are (in general) probably even more particular about their experience compared with typical PC gamers.
User manuals were fairly thick at the time, even for games that were otherwise uncomplicated after a few runs. This is most likely because tutorial missions were not used as frequently back in those days. (Correct me if I'm wrong on this, though.)
Around the turn of the century, game boxes also became more sensible in size, most likely due to economical and logistical factors. I remember one day walking into a Best Buy and noticing that all the games were in smaller boxes. It felt wrong at the time. Nowadays when you buy a game that comes in a physical box, you're basically getting a game key inside with a DVD and a paper slip, and that's it.
While content in game boxes tends to be fairly light these days, you can of course still get some sweet goodies in the form of collector and special editions of games. While they're often pricey, you can usually get those releases at a significant discount years later. Take the Elder Scrolls Anthology Edition, for example. If you're a frequent Dealzon user, you'll know that when on sale, the Anthology goes for $15 to $20.
It's interesting to think that in just a few more years' time, physical boxed PC games will become even more scarce as digital games become more and more the norm. Here's hoping those select special games, publishers, and developers will still release interesting physical editions, with plenty of goodies inside so we can show our uninterested grandkids decades later.
...and our kids will probably laugh at us for playing games that forced us to bask in the glow of an LED display, right as they don their VR / AR gear.