Yeah, and they were doing that well before automatic online monthly payments were a thing!! People actually took some minutes every month to send them money.

But, to the point, it's not like you could accuse the Zach bros of "selling their own image as a brand". They just have this thing they are making, a healthy relationship with the community (but nothing histrionic like your average youtuber), and people just gives them money because they want them to continue making that thing.