... I didn't create the original Yahoo Group and I don't considerSame for a handful of groups where I'm a co-owner.
I had never used Stripe and I knew I wasn't going to be successful inI believe that the members need not do anything with Stripe, they just make a CC payment much as you did to pay for Premium Plan for your group. You have to set up an account with Stripe because you're *receiving* the funds.
Here is my idea, for what it's worth. Provide a way for each MemberI like the idea of having an easy way for members to donate to the groups they value, with those payments going into an account balance that accumulates until the group's next plan payment is due. At which point the group's payor is billed for the deficit, if any.
Any excess would have to carry forward, because this is the "simplified" Donation option, and the group's payor has no Stripe (or other) account into which the excess could be forwarded.
A significant problem with such an arrangement, and the current donation mechanism, I think, is the micro-payments problem: how to minimize the overhead cost of collecting the money. With the current Donation mechanism this amounts to 30 cents + 2.9% to Stripe, + 2% to Groups.io. So a member donation of $1 yields 65 cents to the group's stripe account, 33 cents to Stripe, and 2 cents to Groups.io.
That's not unworkable, and not out of line with other payment processors, but given that member contributions to a group are likely to be on the low end of $/transaction it does seem wasteful. However, aggregating a member's donation into a single payment across many groups would both make it easier for the member and help lower the impact of that 30 cent per transaction cost.
That said, I imagine a histogram of number of subscriptions per account (excluding the Updates group) would likely peak very near 1, with not much of a tail. Probably a secondary peak representing group owners and mods, who as a class I suspect are far more likely to subscribe to multiple groups. Coloring the histogram bars by Role would be interesting (and might surprise me).