Thanks FREE866! Two thoughts on the matter:
1. Arguably, those commentators may be right in the long term, at least if you view things through the lens of the Austrian School of economic theory. The 80s were an unusual economic time, with high interest rates and enormous growth stemming in large part from deregulation and tremendous government spending. Some argue that a fair amount of this growth comes from foolish and unsustainable federal policies.
Nobody who makes this argument could possibly know when the current debt-funded economic system will collapse under under the weight of a lack of investor confidence, but their point is that the current system is not sustainable indefinitely. And I think that's true, just like anything else under the sun--nothing lasts forever.
Now, the current system might continue to do well until 2050 or beyond. Who knows?! And, of course, nobody knows who will win and who will lose in the next economic system, either. Probably the best/most balanced summary that I've seen is here:
https://www.lynalden.com/fraying-petrodollar-system/
2. It's said often that stocks are the best investment vehicle, but that's not necessarily accurate. I may be quibbling over a few tenths of a percent, but I've seen data on REITs going back as far as the mid 1990s (alas, I can't remember where). And depending on the start and end dates, REITs sometimes even outperform the S&P 500 over long periods!
And the correlation between stocks and real estate is moderate (~0.60, if memory serves), making REITs a solid, high-yield diversification tool.
I've spent some time looking into REITs in anticipation of putting some of my own money in one. For some reason, people seem to think they are riskier than stocks, but I can't figure out why that would be. They're less tax efficient because of federal regulations about dividends, but that would hardly matter in a tax-sheltered account like a 401k or an IRA. Maybe people are still shell-shocked from 2008 ¯\_(ツ)_/¯
Anyway, Paul Merriman writes about REITs in a pretty matter-of-fact manner for MarketWatch:
https://paulmerriman.com/10-things-need-know-reits/