GAMCO Investors founder and CEO Mario Gabelli is one of those investors that proves it’s possible to beat the market even over long periods of time (the Gabelli Asset Fund has beaten the market by 2% on an annualized basis since 1986), so it’s a little surprising that he doesn’t even bother to tout his own industry in a recent Bloomberg interview. “If I’m an individual investor and I have $100,000 I want to invest in the next five to 10 years, I’d have no problem doing what Warren Buffett recommends — buy an S&P 500 index fund,” says Gabelli,…