Patreon has placed itself as a 'membership business' as we can see from their copy. The reason why Patreon did not implement this already, is that it'll affect

Patreon has placed itself as a 'membership business' as we can see from their copy. The reason why Patreon did not implement this already, is that it'll affect their recurring model. If supporters find out that there's an easy and straightforward way to support, they are less likely to sign up and opt for monthly recurring donations (except for exclusive content). Also, nothing is stopping us from enabling recurring payments :) We believe it's best to focus on solving an important problem than be the jack of all trades. Hope that makes sense!