I suspected that this was the case (that it's the real angel Patrons that funds the game developers) but had little data to support it.Believe me or not but high-tier Patrons, $25 and above per month, are the most royal supporters a dev has (the core group of supporters). They rarely change their tiers compare to low-tiers, who switch tiers between $1 and $25 or cancel their support completely in between updates.
I once tried to get in touch with a $100 supporter but he ignored all my private messages. Same for dev trying to contact him about his custom render request. No response. And he continues to pay $100 each month without saying a word. Another high-tier patron told me that he likes the art and consider his pledge as commission fee for his custom render. And yes, he has a good paying job and pledged already over $1,000 to the dev. A $25 tier patron told me that he supports a few other dev at the same time - each month $400 to $500 in total.
Those guys are the real people who are responsible that devs can continue to work on the game. Upgrading their hardware to create images with more details in it and render faster. Otherwise all games would have grainy renders with less details in it. (However, seeing the high demand for "crunched/compressed" game here I'm not surprised that people are not interested in quality but actually in quantity.) More renders, more updates... Let's be honest here, those guys would also fap to a stick-figure if they ares labeled as "mom" and "son".
Having this first hand experience I think the pirate's accusation of milking/scamming their patrons is no longer valid. Of course they are exceptions for a few special devs, but the majority of devs aren't milker/scammer or lazy.
$500-$800 a month for a patron like that is not a lot of money if you make $x00k/year.
Honestly, they just want the dev to do what they do and be successful and they think of themselves as an angel investor.
Their return is (besides the obvious sexual satisfaction) to have the satisfaction of seeing a game they love being developed and successful. That's enough for them - don't need the extra money. Does not matter if the developer is late a few months - they are busy at work anyway. They just want it right.