It is rare but I have seen creators making use of sites like Patreon, it just depends on the status of IP ownership. For an example, Motoka Murakami has a Patreon for his series Jin which I would consider a niche title (Medical drama about a Brain Surgeon time slipping into the Edo period) all in English. It still got fully released through the normal way in Japan, but I'm guessing he personally felt there'd be enough interest in the west and was able to self-publish the English version without much concern from Japanese publishers.
You also have cases like the early years of Watamote where it received a lot of attention from places like /a/ and /v/ buying large amounts of the physical Japanese volumes, which greatly boosted its popularity internationally and domestically. It's not like the Japanese publishers are entirely oblivious and there has been a noticed increase of them pushing out services specifically for international markets (Jump, Bookwalker, etc.) While you can't directly send authors money you can certainly now more easily buy digital (sometimes physical) editions of their work that don't require jumping through a million hoops with forwarding services.
