I can't see Coinbase adding any altcoins until the coins/tokens have proven themselves solid (tech-wise).
This coming from a n00b though. Just got into cryptocurrency last week, and TRX was one of the first altcoins I've invested in. Don't have all my eggs in that basket, but if it at least goes back up to it's all-time high though, that will be a nice return.
See a lot of folks saying they'll sell off at $0.20-$0.30 though. How's that gonna affect the price if/when that happens??