Ignoring the lack of updates if the game is buggy, games back then were also more focused on quality and make gamers replay the game with unlockable features based on skills, not money. I can't count the number of times I played Metal Gear Solid games over and over to unlock new features playing the hardest difficulty and with handicap features, and also to find Easter eggs. Speaking of Easter eggs, you'd lose a number of hours exploring every nook and cranny finding them!
Do you have an example?
I knew kids that bought strategy guides, I worked at a game shop that sold strategy guides, and as far as I could tell they were for chumps. People who has more money than creativity.
Cosmetic DLC feels like it's for chumps too, but it's lucrative. The best example is going to be Simon's Quest, without a doubt. The strategy guide was in an issue of Nintendo Power. I'm sure they were also happy to let social pressures on the playground either sell the strategy guides or the game just by word of mouth as kids discussed how to progress in the game. A Link to the Past is full of this stuff too. The game grinds to a halt at several points until you happen to find a macguffin that the game doesn't even tell you that you need. Without the strategy guide, you could end up finding those things by spending tons of hours exploring every corner of the map, but by today's standards, we'd call that padding.