Its true enough. Its been nothing but downhill for Tim, Kon, and Bart after the 90's, and Cassie never really ever amounted to much. And thanks to DC continual effort to make them work, Teen Titans became a casualty. Teen Titans credibly has become comical under Tim's generation.
Dick and Wally are the most successful out of the group, but they were all flying high during NTT's hey day. And then there's Cyborg, who is on the rise, and Starfire, Best Boy, and Raven have done ok for themselves. The cartoon helps.
Steph yes, i mean she started as just a supporting character for Tim, but slowly but surely became more then that. Cass though i don't know.