Historically speaking the group that has been causing the rally is obviously much bigger. Bitcoin has been going up since 2009, and at the price it is now, it is still very good considering where it started.
I agree that the price is still high, even $5000 would be a good price.
But how to know
why these people that have caused the rally invested?
Since about $3000, price upswings have been related to hopes to get "free coins". It may be a simple correlation and not a causality, but I think a big group has invested in Bitcoin in those last 3-4 months with Bitcoin Cash, Bitcoin Gold and Segwit2x "free coins" in mind.
I for myself am bullish long-term, but in the mid-term I believe there
could be a bear market (e.g. 2018-19). $6000, an important mark, have been broken now (that would indicate at least a short-term bear market), although it was at a moment with heavy speculation moves between BTC and BCH. So the signs are not really clear.
Taking everything into account, I think the question "will we see 7800+ prices in 2017 again" is still a 50/50 bet.