Who is saying 2% to 5%? Many economists (a number of whom are Nobel prize winners in economics), financial analysts, CFP's. The heads of major financial & investment firms. I read financial & investment articles every day, and I pay particular attention to articles from sources like Fortune, Barron's, Forbes, Kiplinger, IBD, Market Watch, WSJ (and its editorial board), The Street, etc. This isn't secret info - it's public info from reputable, long-time, well-respected financial sources. A hefty number of those folks I named above have been saying, ".... don't expect the historical 10% or so from the markets for probably the next decade."
Their info doesn't make my wife and me get out of the markets entirely - for sure - but it makes me re-deploy $$$ into safer, more predictable, dividend-paying investments. We're still positioned for growth in certain areas as well. But with chaotic instability in our markets that turn on social media BS & whims, we've taken a less volatile path. I've been heavily studying investments since 1977. This period of time is unprecedented in my lifetime.