The extreme amount of regulation around becoming a publicly traded company makes this infeasible except for large, mature companies that don't really have much

The extreme amount of regulation around becoming a publicly traded company makes this infeasible except for large, mature companies that don't really have much asymmetric upside available anymore. These regulations were created mostly in the name of protecting "mom-and-pop" investors, but the net effect has mostly been to shut "mom and pop" out of the most lucrative investments. This might or might now be a good thing, depending on how valuable you think it is to decrease variance for "unsophisticated" investors.