I don't know tax laws in other countries, sorry. Some of them have similar tax-sheltered retirement accounts though.

The 15-30% is if you're being very aggressive (but not reckless) with leverage. You wouldn't get that much in Wealthfront's default portfolio, or a target-date mutual fund, for example. That's also on average over time; some years will return much more than 30%, and some will lose money, and, of course, past performance can't guarantee future results. Broad market conditions could shift enough to invalidate any strategy. But you can do better than index funds. Compare PSLDX to SPY over the same period: https://www.portfoliovisualizer.com/backtest-portfolio?s=y&t...

Notice that they both had ~50% drawdowns, bottoming around 2009, but PSLDX was not that much worse, and grew faster afterwards. SPY also had a slightly worse worst year. PSLDX had significantly more volatility, but the returns more than made up for it, giving it a better Sharpe ratio than SPY. So not only are the absolute risks comparable, but the higher Sharpe means that if you leverage PSLDX down to SPY's volatility (by keeping a 17% cash balance), the drawdown was smaller and the return is still higher than SPY at ~15% instead of ~11%.