You’re making an artificial distinction. You wouldn’t call Buckingham Palace a social program, because it doesn’t benefit society. It is however an example of the proceeds of wealth redistribution in exactly the same way Medicaid is (except that it’s an example of redistribution from everyone but the richest to the richest. It’s precisely as likely that you’ll discover a monarchy that is run without regard for self-interest as it is that you’ll find a democracy that is run that way.
As for the historical tax rates, the largest difference between now and early times isn’t democracy, it’s that better enforcement mechanisms exist (mainly the possibility of mass imprisonment and the fact that respected borders between nation-states limit options for fleeing from authority). Some quick Googling told me that the only two countries I can think of which could test this question (Jordan and Swaziland, which are strong monarchies that don’t have resources to fund their governments) both have tax rates roughly similar to the US. (Jordan has 16% income tax and a 14% VAT, Swaziland has a 33% income tax and a 14% VAT)