So uh.... I would like to clear something up. Basically, art sells if people find it cute, right? So then someone like me who finds most people's idea of "cute" to be a repulsive disease to the eyes is just straight-up fucked, right? Or am I missing something? What is it exactly that people want to see/buy?

Different art sells to different people. It just needs to be good-ish and rightly priced.
well most people here are looking for art of their pets and because subeta art is fairly chibi-ish I guess it's normal for people to look for that sort of style, but there are probably lots of people here looking for something more realistic. so it really depends on the website. In Flight Rising for example more realistic art sells better, because the pets there are more realistic looking.
different people want different things. some people want cutesy pretty drawings, some people want gorgeous realistic paintings, some people want horrific monstrous creatures - some people want all of those things! if you put your work out there i'm sure there will be at least a few people interested in whatever it is.
What makes me happiest is drawing things in my own style/vision at people's request; if you're looking for something to stand out, then just draw like you always do! Please don't feel the need to adhere to a cutesy/realistic/gruesome/etc style if that's not something you like drawing (the most important part - fun.) Just draw what you like, how you like. The "sell" factor there is your unique style. Own your own style, be the leader, and people will be sure to follow. TL;DR don't try and force yourself into a mold that doesn't fit for the sake of the enjoyment of others when you could enjoy yourself and follow the beat of your own drum while others inevitably follow suit. There's nothing wrong with having different preferences when it comes to art!
I've found that the price has a huge effect on weather or not someone wants your art, unfortunately. Even if your art is grotesque, if it's cheap enough people will buy it.

A lot of people really like Adoptables. They're easy to make, easy to color, and can have millions of different designs, and they're normally based off animals and/or other creatures (mythical for example). DeviantART has many artists that create these for sale. The average price of an Adoptable can vary but between 1-5$ is the norm. I've seen some go for 10-25$ though.