Ok, so why did XRP suddenly hit $3 (and above) in 2017 and went down? I would go with the theory saying that it reached high because banks and businesses shared their positive feedback about XRP. However, the actual adoption and the further domino effect might take 5 to 10 years, but it will (since XRP has already proved to be a reliable tool for cheaper and faster global transactions that can be effectively used by big enterprises). The question is when and how fast they will adopt the new xCurrent framework that takes the process to the next step. Once they do, the domino effect cannot be avoided and the price will hit even above $10. The question is when and how fast. That's why I am pushing for XRP being a long-term investment option now.
I think it's a good long term bet. As for why the price increased and dropped so dramatically, I think a big part is that XRP is really big in South Korea, and the coinmarketcap price was skewed by the Korean exchanges - at one point about $3.75, but never above $3 on non-Korean sites.