One additional thing that would make either crowdfunding or outside investing on light novel licenses more difficult: the fact that many light novels are ongoing series, with regular new releases.
Under normal circumstances, these new volumes are actually a separate license, not "automatically included" with the license of previous volumes. For an official licensing company, this isn't really an issue, so long as the company internally accounts for the cost of future volume licenses and commits to licensing said future volumes.
But if a series relies on outside funding, whether from crowdfunding or an individual investor, then the licensing of those future volumes may need to rely on said outside funding as well. And, well, what if that funding isn't there? What if an economic crisis happens and people aren't able to contribute enough to crowdfund a new volume? What if a volume ends up taking a story in a direction that an individual investor doesn't like, and they no longer want to invest in future volume licenses of that series?
Putting aside crowdfunding, which mainly has the aforementioned issue of trust, the idea of an outside investor putting all the money for a series up-front would only really be feasible for a series that has been completed. (And even then, there's the chance that a new volume will come up for that series anyway...)
