You're mostly right. Except there's money to be made during mad dips with the obligatory bounce back (or at the least increasing BTC count even if dollar value diminishes).
There's also money to be lost when the market moves faster than that for which you have prepared.
But yes, day trading (without borrowing aka margin) and with .25% fees .... it's hard to consistently increase money value and BTC count.
In BTC, I found it pretty easy. Until the moves got unpredictably violent. This is not the sedate stock market. This is Bitcoin. It do dat.