Your probably right no best year in cryptocurrency because cryptocurrency in order to have high value it depends of the high demand in the market, if we want to earn more profit from cryptocurrency we must find out what is the best crypto and having high demand in crypto market.
there is no best year on Crptocurrency, and they say the best year might be in 2017 Crypto can go up or the Bull market, so they get a lot of profits and they get rich so they say the best year in Crypto currency.
the Crypto market is unpredictable, when Crypto goes up or down nobody knows in the years when Crypto will Bull nobody knows.