Yeah it wouldn't have been hard to just knock out an email each month... except only a few hundred people would see it. I'm convinced that the main reason she doesn't do anything on patreon is that it's not public.
I subscribe to someone's substack, and they offer two levels, a free subscription and a paid one (discounted if you pay upfront for the year) and do two emails a week. One for everyone, free and paid, and a second one for those who pay.
I'm sure Jack could have offered something like that, maybe with the free email going onto her website a fortnight later (content already written, so no extra work), and different tiers of electronic rewards for the paying subscribers (an extra email for everyone, then the next tier gets high quality photos suitable for printing, the next tier gets a birthday card in the post, or whatever). The huge and unwieldy list of physical rewards she should be providing every month must be exhausting and frankly terrifying.