anybody who stopped trading during the past 2 years and wants to start again this year must not do it and should stay away from trading. because someone who can not make profit from all market conditions is not a trader, they are gamblers who rely on constant pumps to make profit and since that is not possible they should not risk their money or they will end up losing their money again and again until they are broke.
I believe this cannot be said without adding some nuance. From my time trading forex, I agree that in principle a good trader would have to be able to make money in all conditions. HOWEVER, to me this is mostly due to the fact that you can go both long and short on all pairs. Going short in forex is extremely normal and a highly common activity.
Yes, if you can go long and short you should be able to make money in all market conditions. Since most exchanges only offer long positions, and the few that do offer short positions only do it for a few coins, it is extremely difficult to make money if you know the chances on a decline in price are constantly higher than an increase in price.
Can you make money with going LONG?
Sideways: yes.
Uptrend: oh, yes.
Slight downtrend: maybe
Strong downtrend: very hard.
you actually don't have to short to make profit from a dumping market. it is possibly by only being familiar with 2 market movements: recovery after a
reverse bubbleTM and attempts to pump the altcoins after their death leading to
dead cat bounces.
Exhibit A (ethereum dump during second half of 2017 from ~June to December and its dead cat!)this is during the time where bitcoin was bullish and altcoins were declining every day. as you can see every time there is a sharp dump in ETH price, it is followed by a "correction" reversal that could be used to make small but good profit by simply buying the dip. and the reversal is long enough for a trader to make sure it was a "dip" and join in the follow up short term pump as long as he pulls out just as fast to avoid the next dump.
Exhibit B (ethereum failed attempt at pumping during 2018)this is during the time when bitcoin price was nearly stable without any moves either up or down.
as it can be seen after a long time of dumping where it slows down a small accumulation (~1 month) starts and then an attempt to pump it is started. since dumping was slowed down before the pump could be long and the profit was good (max 55% in ~1 month) but it continues dumping again as soon as bitcoin price drops in January.
Exhibit C (the most recent failed attempt at pumping ethereum)this is the time when bitcoin price was stable at $10k for about a month and it ends with the ETH dump at the same time as bitcoin dropped below $10k again
the overall dump of these 3 is the current -88% but as you can see during all the dumps there has been a lot of profit without shorting!
and that is the
smallest example i posted here. there are other shitcoins better than ETH that had the same trend but with a much bigger profit. for example those that got pumped 1000% during their dead cat bounces.