But the S&P500 has crashed, a few times in recent memory. It doesn't have to go to 0, it just needs to not be a perfect bull market all then time. If you're at 80/20 stocks/bonds and the market crashes your allocation might shift to say 70/30 so when you rebalance you're selling bonds to buy stocks. Its a way to perpetually buy low and sell high regardless of what the market does.

Well, they have nukes, but they're also morons. If that side of them materializes, they'll probably crash the currency value, which also raises S&P, and if you are leveraged, hopefully by more than the currency crashes.