I font think anyone can really predict what will happen to bitcoin tomorrow, talk less of saying 4 years, we can only speculate and wish it could go up. For me I think it can reach its peak again in the next 6 months.
with all the growth that has occurred in BTC for a number of months, I am very confident that BTC will reach its peak in the near or far future, but even if it is not impossible, BTC will come back down so we still have to be careful and continue to monitor the BTC movement.