It is true that trading can make money quickly. In my opinion, it is very difficult to do this job, even though you have been equipped with knowledge for years, sometimes even those who are experts can still experience losses. It seems that the trading you are talking about is trading with long-term methods whereas above you are talking about short-term. What you are talking about is of course widely used by investors because it is much safer than short term. Indeed, all investment methods require extra patience, time, expertise and experience to get the results we want. I think only a few people are truly successful in this job as a trader.
When you can make a profit from trading you will think that trading is easy but slowly you will start to realize that it is not always easy even though you already have enough knowledge, what is easy is getting knowledge about trading but making a profit is not easy.
Under certain conditions, maybe you will be able to make profits quickly, as I experienced when I was bullish a few years ago, because the market tends to always go up, you just need to be patient for a while when you buy coins but the price goes down in a short time, the price will go up again and you can make a profit, but everything will change when the market is bearish and Bitcoin starts to fall, so altcoins will be even worse, so many traders become holders when they don't want to stop loss.