There's a ton of money invested in everything, so everything is yielding pretty meh returns.
C'est la vie, you're not going to outsmart the market and there's no secret idea that's going to make you rich. You already said you're not interested in real estate, and that's probably your only/best bet for what you're going for.
I'm actually a fan of efficient markets theory. I've seen the research that passive investing wins the highest yields. I've tried making predictions and performed worse than coin flips. Yet, the markets can be shown not to be "efficient" or even "markets" in the sense that investors have a choice to buy or not buy.
First of all, not all dollars are invested based on the choices of individuals with incentives to earn high returns. Pension plans, ETFs, some sovereign wealth funds, and individual 401(k) plans must make regular purchases no matter what the price. Thus, there is a steady buying pressure that is maintained no matter how high the market goes. Furthermore, the managers making or automating these buys are doing so on behalf of others (or thousands of others) and have no skin in the game themselves. Thus the "market" is not a "marketplace" at all. It's kind of an automated buying machine that doesn't stop at any commonsense level. How does price discovery work when almost everyone is passive? This market is very different than a few decades ago, when the theory was proposed.
Second, there is evidence indicating that the vast majority of the S&P 500's post-crisis growth was due to government stimulus. If this is true, an assumption of efficient markets theory doesn't hold in the real world case. Price is not based on information, but on price supports.
http://finance.yahoo.com/news/the-fed-caused-93--of-the-entire-stock-market-s-move-since-2008--analysis-194426366.htmlPerhaps at any given timeframe it is impossible to predict which investment option will outperform. However, if an offensive game is impossible because the markets are efficient, I wonder if a defensive game is still a possibility. Maybe 1999 and 2007 were good times to turn off autopilot and play it safe, because multi-trillion dollar bubbles could be seen. Maybe the hyperbolic arc in Chinese stocks in early 2016 could have been recognized by a human as a sell signal.