3 ideas
Being rich is not a matter of high income or visible possessions: someone with a large salary who spends most of it and carries debt has less real wealth than a modest earner who saves heavily. A household that saves a large share of an ordinary salary can outpace high earners who spend to match their pay.
A young investor who is a net buyer of stocks for decades should prefer falling prices, because each regular contribution buys more shares at lower prices and the fund's dividends buy more too. This reverses the usual emotional response to crashes and turns them into buying opportunities rather than reasons to panic-sell.
Before costs, the investors in a market collectively earn the market's return. Active funds subtract expense ratios, trading costs, sales loads and taxes from that return, so most of them must trail a low-cost index fund.