It actually does take much more investment expertise than the average American has to know what a Vanguard Fund is, to know that it's a safe bet etc.
Why aren't basic finance classes taught in grade schools anymore? How hard is it for parents to teach their kids to save 10% of their income, and to put it into an IRA?
Edit: Before anyone points it out, I know the IRA is a relatively young investment vehicle (the 70's). Swap IRA for any sane long-term savings and retirement plan.
Nothing is without risk. This is, perhaps, the first financial investment lesson we should teach our children.
30 year US Treasurys are currently ~2.7%. Assuming someone saves 10% of their pre-tax income each month between the ages of 25 and 55, at that interest rate, they can look forward to 5 times their average annual income to sustain them through their last 20+ years of life. That's a 75% cut in income. Stocks are theoretically higher yield, but as others have argued, normal people shouldn't have to worry about stocks, and more importantly, there's a justified fear of market crash, which could be... appreciably lower return than Treasurys.
It should be possible to buy CDs at a few points above inflation. This was the historical norm. People shouldn't have to "invest" at all to preserve and modestly grow the value of their earnings. The vast majority of people have no business owning stocks or bonds. The only reason you can't get a decent interest rate is the crazy monetary policy of the last 40 years.
It's funny how most (all?) government policies result in a wealth transfer. If it's not directly buying goods and services from a corporation on behalf of the people, it's a policy to encourage the people to spend on one thing instead of another. There's nothing inherently wrong with that, but it's good to notice who stands to gain.
Name a historical period of longer than 15 years in which the market as a whole has lost money relative to inflation. That didn't even happen across the Great Depression.
http://www.angelfire.com/or/truthfinder/index14.html
http://www.dogsofthedow.com/dow1925cpilog.htm
Furthermore, market history did not begin in 1910 in the United States. Stock markets go back hundreds of years in many countries. A global long-view perspective is worth a lot more than 90 years of US data. And from that perspective "stocks for the long haul" have very often been a bad idea.
The figure I was remembering was actually about a 60/40 balanced stock+bonds fund like VBINX, which is what I'd recommend to anyone anyway.