I know that if those games were released today there's no way I would play them for long and I'd recognize them as poorly designed. But when I was a kid every new game was a big deal and so I pushed through the puzzles (I felt certain ones were ridiculous, but generally just accepted them as what adventure game puzzles were). Sometimes I'd get stuck and come back months later. Ultimately I beat most of the King's Quest and Space Quest games, even years later.
It's hard to imagine that today with the unlimited buffet of cheap or free games. The constraint used to be money, now it's time. Even for kids.