I like Ethereum and think they have a lot going for them over the next few years but I'm not sold on Ripple, they're centralized and it seems like everything they do goes against the goal of cryptocurrency so I think eventually people will desert them.
you need to know two things.
first is that people only get in altcoins that can give them profit. then don't care about anything. they can be centralized, buggy, scammy, or they may not even exist in reality. for example i have seen people trade coins that are no longer generating new blocks, there literary is no more mining but they are being traded!
second is the fact that centralized coins like XRP and ETH have centralized funds to pump them and keep them alive. they are not like decentralized altcoins that solely depend on the community to keep them alive. so they won't go away that easily.