I have less issue with a founder's decision to invest in an unproven market than I do with a VC or PE fund choosing to dole out money to those founders because those investors are convinced that they can win big if they pick the right horse. You're gambling your time and livelihood that you succeed, sure; hopefully you have a solid business plan. But the people around you are gambling (probably with other people's money) that you make them fabulously wealthy.