It wasn't. The people saying they miss 2nd gen, don't really miss 2nd gen. They miss that time of their lives when they were probably at school and had no responsibilities while now they're probably adults with jobs.
All different kpop generations have their good and bad sides, if kpop isn't enjoyable anymore for you fine.
Kpop has changed yes, in the same way 2ng gen changed from 1st gen. It's how the world works. If new kpop isn't for you then fine.
But don't go around saying "back in my day it's was better".
It's pathetic and gives "deranged grandpa yelling at kids in the yard" vibes. Not a cute look.
Edit: you all are literally proving my point in the comments. I'm not saying 2nd gen was bad at all. But you still are desperate to point out how 3rd and 4th gen sucks and 2nd gen was better. We get it. Times change. Move on.