Due to relaxation in SEC regulations in the past decade or so, it’s now possible for non-accredited investors to invest small amounts (starting at $100) in non-public companies. This mechanism has good affinity with the progressive movements penchant for small-dollar fundraising. That is to say, the muscles we’ve developed for small-dollar campaign fundraising can be repurposed to fund for-profit companies producing innovations in our space. Unified and Shire have pioneered this approach. (I am an investor in Unified -Shai Sachs.)
There are challenges with this approach. This mechanism is not perfectly suited to all companies - some corporate missions are simply too complicated to explain to small-dollar investors. Furthermore, it does carry with it additional reporting requirements for the companies raising funds. Finally, it can be challenging to raise significant funds in this way - we have yet to see small-dollar crowdfunds that raise the tens of millions of dollars sometimes needed for private companies.