It also depends on the subject. For instance, there's an ex journalist in my country pulling in €20K/month on Patreon by making videos on corruption in the country. It resonates well with the audience which doesn't seem to be able to get similar content from the newspapers/TV channels. There are some random writings on Substack,but there are also those that aren't covered much in more popular media, which leaves a gap and some writers are happy to fill it.