A lot has changed in K-pop since even the early days of 3rd gen – the trends, the style, and the fan culture are just some (but not all) things that have evolved since, say, 2012. I'm sure a lot of you like older groups, and I'm curious to see where you think they'd be if they debuted right now, in 4th gen. Cuz K-pop was way different just two or so generations ago.
For my faves, TVXQ...let's say they debuted as they were in 2003 (i.e. OT5). K-pop stans nowadays would probably hail them as a savior with their light concept and focus on vocals. And even nowadays, Pinterest kids are falling for the magic of debut-era Kim Jaejoong. Not to mention being under SM would also be a benefit for them. (Let's disregard the fact that TVXQ basically got SM out of their flop era, this is a thought experiment. I won't even get into the problems I'd have to disregard to do H.O.T., my other faves...)