It’s not exactly anyone’s followers’ responsibility to promote their art for them though.
Like, don’t get me wrong, I love getting reblogged and feel really honored when people think my stuff is good enough to belong on their personal space. I totally have xkit’s tag viewer installed so I can smile at nice tags people leave on my art. But if something of mine doesn’t get a lot of circulation, I take that as a sign that it’s not something people are interested in seeing. And if you’re interested in getting attention/business (as opposed to drawing for personal fulfillment), then appealing content is on you as an artist.
And then there’s the matter of audience, where tumblr is mostly young adults interested in fandom. So a poorly-drawn joke comic with recycled Parks and Rec dialogue about a popular cartoon is more likely to get 30,000 notes than a painstakingly-created digital painting based on your friend’s original novel. It sucks. But tumblr is not an ideal medium for promotion for certain types of art.
My crappy Scourge valentines are at almost 2,000 notes. I put a fraction of the effort I put into my best work (which averages around 150 notes) into those. Reblogs are not always a great indicator of what’s good.
tl;dr quit bein passive aggressive about how people organize their blogs