I like this style of thinking. A couple quick notes:
1. Various U.S. presidential candidates have proposals for “democracy dollars”, which are similar to philanthropy vouchers, but scoped to political giving. AFAICT, they have a different macro goal as well: to decentralize campaign financing. See https://www.yang2020.com/policies/democracydollars/ and https://www.vox.com/policy-and-politics/2019/5/4/18526808/kirsten-gillibrand-democracy-dollars-2020-campaign-finance-reform
2. I agree that non-politics can be systemic. See this post that expands on your idea of “what if everyone tithed 10%?” https://forum.effectivealtruism.org/posts/N4KSLXgr6J7Z9mByG/an-argument-to-prioritize-tithing-to-catalyze-a-paradigm
3. It would be interesting to see philanthropic vouchers tested in the EA community. Kind of like a reverse EA Funds/donor lottery, where an EA donor gives lots of EAs vouchers (money) and then the EAs donate it.
Link to an ongoing Twitter discussion with Rob Wiblin, Vitalik Buterin, etc. here: https://twitter.com/glenweyl/status/1163522777644748801