Hmmm, this is tough because I consider Red Velvet my all time top favorite girl group. They are just so freaking talented, and it's hard for me not to root for the best singers to be the most successful. Even as a fan, I would often cringe at some of their title tracks. Like "why, SM? Why not give them an easy, general public friendly hit?"
I think SM dominated 2nd gen so much with snsd and other groups, that since then they're trying to prove that they can continue pushing the envelope and find new ways to succeed, rather than just following the trusted snsd blueprint. Groups like nct are also not that gp friendly all the time. They're still attracting some of the top talent because they're sm, but honestly if I was going to be a trainee I might go to a different company that wouldn't sabotage my success. JYP wasn't doing that well right before twice debuted, and was happy to pick up the baton that snsd dropped and use their winning strategy of pretty, cute, bubbly, catchy concepts for twice, and we can see how well that worked. YG is happy to just continue to stay in their own lane. 2NE1 worked well for them, and they decided that if they had an all visual version of 2NE1 it would be even more successful. SM seems to be filled with creative directors who are more interested in putting out something avant garde or jazzy, regardless of how popular it becomes.