Historically the S&P 500 has returned 10.7% over the long haul but lets say you could only expect an annual return of 8%.
If you invested $100 per month, at the end of 40 years you would have $702,860. $150 per month would put you over $1 million with very little risk.
But, of course, everyone wants to be a millionaire in a year with a couple of thousand invested. So they buy CMKX and lose what little money they have.