Your post tells me: you can't
i cant, but maybe others can?
Yes there are, r0ach and spotnik. They are BTC and ETH whales, trying to buy as much eth as they can while its cheap.
I assumed there must be more than just 2 people out of the whole of bitcointalk who manages to make a living by trading though. r0ach and spotnik may have just been in the fortunate position of buying bitcoin in the early days and being whales these days so can afford to trade larger amounts. It would be interesting to know how much they make per week from trading and how much they have to actually trade to earn that amount.
Yeah, others can but it's not like that was many people. These markets are illiquid as fuck. Not really a lot to gain in alts anymore. Scammers and monkeys spoiled it.