This doesn’t touch on one key difference between games now vs. games then: there were some secrets in games that you just didn’t ever know about unless there was a (printed) walkthrough, or through the word of mouth of friends. The Legend of Zelda is a great example.
Nowadays, many games can be 100%’ed without even having to jump online or ask someone for help. I’m not saying that’s necessarily a bad thing.
I’m playing the Metroid Primer Remaster on the Switch 2 (originally for the GameCube), and even it can be 100%’ed without having to look much up or without even a manual.