It's not true. You can make profit in many ways in crypto world. Sell high buy low, you'll just need to have no emotions and a lot of patience when it comes to crypto though.
Which brings more profit?
Buy low sell high
OR
Pay 1-2 BTC to create a coin
Premine 80%
Launch
Let it hit exchange
Dump
?
One is "luck" while other is guaranteed profit. People choose second option over first one. If you're small time trader/miner you're relying on mercy of those who're playing the game when you can take control of the situation and create your own altcoin. lol. All it takes is $500 and you get return of $5000 within a week or LESS!
lol..that's like 99.9% of coins are created by someone who has no business in crypto world.