To address 2 points that have come up a lot:
1) It's a free time issue, and it's not long games, but your lack of free time that is the problem
This is a weird one because while you can beat 100 hour games by playing an hour a night, people might want to use their gaming time to experience more stories, worlds, mechanics and adventures, as opposed to spending it all in one game doing endless side tasks. If games were shorter, they'd fit more games into their free time. If you have 100 hours free, some people would rather play 5 games that take them 20 hours a pop, than one game that takes them 100
2) Just quit when you're bored and don't finish them
This suits some people, but most single player games have a story with an end, and that's often a part of why people play games. If you always bail on every game at the 20-50% mark, that can feel like watching the first half of every film you start. It's not ideal and not something that will suit everyone
To conclude, I don't mind long games personally, I just make sure I'm always playing shorter games alongside them, but there are a lot of reasons why 100 hour games are less than ideal for some people, and their criticisms are valid. More so when games have become much, much longer on average over the last decade. To a lot of people that will be great, but it's obviously going to cause problems for others
