The main problem with the patreon model (for software development at least) is that often developers, the few that actually complete a project anyway, at the end release their product for free. This means that for them the only source of income is gonna be during development time which means that the lazier and slower they are the better for their finances that is. You are not incentivized to meet deadlines but rather the opposite. The only way I can see a patreon model work is for art creation, some regular content that you appreciate and that repays u constantly of the money you have invested on that artist rather than the hope of a future project that may never be delivered. Why isn't kickstarter used for this kind of projects anyway? So that if a project is abandoned people gets their money back.