I would just note that this has been the absolute best strategy for ~50 years but its not guaranteed to continue as such. Bond bull is over, plenty of reason to assume that SPX will at least keep up with real inflation but its not the no-brainer it has been in recent history. The monetary regime is changing and that is going to change what is "best" and if you just blindly assume the same strategies will work you may end up in trouble. Ask Boomers holding high % of fixed income in their portfolios about "safe" investments.
A lot of moving parts in the financial world right now, if you're low conviction/knowledge on investment choices I would say its not a bad idea to at least hedge a passive SPX style position with some sort of "debasement" holding, Gold/Silver/Bitcoin has a chance to help you stay afloat depending on how things play out. IMO SPX is essentially the US retirement fund at this point so its likely never going to see a protracted fall, because the $$$ printers can't afford that politically, but I wouldn't say its a "good" trade moving forward.
I wish it was easier to give safe advice for investing, but right now everything is fairly risky if you're just going to set it and forget it unfortunately. Happy to have one of our resident experts correct me, but I just can't see the advice that worked 10 years ago (S&P and forget) being as guaranteed as it has been.
EDIT: Adding spoilered. 2025 asset performance. I think we possibly continue to see this sort of thing, setting aside BTC performance as its an entirely different topic. Real assets outperforming financialized assets as our economy shifts focus. Assuming this shift continues and the current regime is successful in their efforts you simply can't continue to act with the same set of assumptions because the entire game board has changed.