Mick Jagger famously said in his younger days that he would rather be dead than sing Satisfaction at 45. Well, now he's 75 and he is still singing Satisfaction. Publicly.

Contrary to what F. Scott Fitzgerald wrote in The Last Tycoon ("There are no second acts in American lives."), there are turning out to be many second acts for entrepreneurs. And surprisingly, these second acts are increasingly among people over 55. There are actually more companies founded by codgers than by kids these days.

Note this recent quote from The Kiplinger Report: "One growing sector in the U.S. job market: Baby boomer entrepreneurs. By 2020, those at or near retirement will launch 25 percent of businesses." According to the Kauffman Foundation, people 55-65 started 23.4 percent of companies in 2012 (the latest year it reported.)

For example, Moneynews reports that the average age of 500 recent applicants for a Florida entrepreneurship program funded by the U.S. Labor Department was 51. The article quotes Andrew Duffell, CEO of Research Park at Florida Atlantic University in Boca Raton, who says older entrepreneurs are increasingly moving to Florida, not for retirement, but specifically to form businesses. Duffell says that his park includes a technology business incubator to assist startup companies and over 30 percent are run by people over 50.

Furthermore, unequivocally there is ageism out there that limits traditional employment for many women and men over 50. (In this regard, human resource strategy needs to catch up with new realities in the job market. More on this next week.) Much of this ageism is misbegotten and stupid, but it also may be why older entrepreneurship is growing.

There was a great article in The New York Times in 2013 titled "Why Innovators Get Better With Age." It notes research by Benjamin Jones of Northwestern University that concludes that "a 55-year-old and even a 65-year-old have significantly more innovation potential than a 25-year-old." The article goes on to state, "If an organization wants innovation to flourish, the conversation needs to change from severance packages to retention bonuses. Instead of managing the average age downward, companies should be managing it upward."

There is a great deal going against small business and entrepreneurship these days. Much of what militates against robust business formation in the U.S. is obvious enough, i.e., unnecessary government regulation, onerous taxation, Obamacare, etc. I was alarmed to hear Jim Clifton, CEO of the Gallup Organization, citing figures from the U.S. Census Bureau that there were only 400,000 startups last year and over 470,000 company closures. Ugh! That trend needs to change not only for the health of the institution of entrepreneurship, but for the health of the world economy itself.

Perhaps 60 really is the new 40. With growing longevity and health consciousness, all of us are going to be productive longer. Perhaps much longer. I cannot imagine myself or most entrepreneurial colleagues embracing a twilight of idleness. More likely, passionate entrepreneurs share the sentiments of Dylan Thomas who said,

Do not go gentle into that good night
Old age should burn and rave at close of day
Rage, rage against the dying of the light.

Amen, Brother Dylan.