You cherry picked the companies though. Take the index for the top companies in some other country than USA and that investment no longer looks as secure. USA did great the past 100 years, many other countries didn't.

Buy VT instead. If thirty years from now the value of every meaningful company on Earth is inflation adjusted worth less than it is now, bullets and farm land would have been the only viable investment.

Usually those indexes are not as diversified as the US index is. Take German DAX for example. It's mostly made up by chemical, car and industrial companies. The post-war German economy did really great as well, but many leading German companies are private. Furthermore, the USA is one of the biggest economies in the world, way bigger than most single countries on their own.

OK, so I didn't make the original S&P market argument, I think they should go bigger and focus on globally diversified broad market funds, but, to get back to my original point, what's the alternative here?

There isn't one. People love to spread doom and gloom without any real solutions. Real estate, gold, crypto, bonds, etc... are all either affected or soon to be affected by these economic conditions. Panic sellers will lose big and folks that don't have the means to weather the storm will suffer. Personally, I still believe in a well diversified portfolio being the best option (as do many), but the truth is, nobody really knows.