I have modified that part to make it more clear that you shouldn’t go heavy into a single stock. However, the statement itself is true. If you want a stock position in your portfolio to be worth $1 million, you have to put a lot of initial money into that position because appreciation is how you get there. It’s not encouraging a YOLO but just stating a fact.
I primarily used this point to emphasize the importance of growing income. That way, you can increase your monthly contribution to your portfolio. You can know which stocks have great potential but if you aren’t contributing enough to your portfolio each month, it doesn’t matter what potential opportunities you know about since you don’t have much capital to utilize.