I am an idiot. Or possibly just busy. Here's a hint. If you visit a Patreon page and see, "Become a Patreon," it's not a generic box placed there that everyone gets regardless of their status. It means you are not (or in my case, you are no longer) supporting that creator. If you are supporting that creator, the box will say something like, "Thanks for your patronage." Obvious, right? Unless you aren't paying close attention. Other than that box, nothing else changes. My credit card expired a while back, and my credit card company dutifully sent me the replacement at the beginning of the card's last valid month. They seem to like my money. Even though I updated Patreon with the new expiration date, they didn't get the memo. It might be because the pledge for that month already posted, and I somehow got marked as "card expired." So, as a public service to others who believe they are still Patreons, check what the box says. (It appears in different places for different Patreoners, so you may have to search for it.) If it's not some form of "Thanks ...," you aren't contributing any longer.

Best of luck with your future endeavours - you have created a following that will support you along the way.