It is what happened in 2017 and even during early months of 2018, but things changed when bitcoin fell down, broke its supports and fell to below $4000 as well as altcoins fell to its nearly the same starts in early 2017 in BTC trading pairs.
I personally make more money mining and trading bitcoin than i make from my average IT related job, in fact if i quit my job today and invest all my time and effort in crypto, i could make 2-3 times more income, but then i'd be stupid, if crypto goes south i would be broke and will have to start all over after having lost all my clients and skills, things will be worse than ever.
It is always better to see earnings that you can get from your works in the forum as additional financial income for your live, not the main or only source.
TL;DR : unless you have a good amount of reserves, then living off the forum and crypto in general is too risky, there is nothing wrong with some extra income from signature campaign or trading goods and services, but don't go balls deep, just in case!