Why is there no support for the R6220?

A few months ago I impulsively decided to try flashing OpenWRT on my dinasaur of router without thinking about the fact that I needed to be online the next day. To make a long story short, after a quick run to Best Buy and failing to pick up a cell signal in there, I walked away with the r6220 after being assured it was compatible with at least DD-WRT and probably OpenWRT. When I finally got around to giving the open source firmware a shot again, I discovered that there is next to no support for this model (I found a start here) , despite a number of positive reviews I found. It was past the return deadline, so I ended up keeping it and thought it might be a cool project to work on once I get a new router. I was hoping someone could tell me why this model doesn't seem to have any open source support, and if feasible what I'd need to know to make a build (or finish the started one I found). I'm not too worried about bricking it at this point, and am always looking for new tech stuff to learn. If anyone can fill in some of the blanks here, I'd appreciate. Thanks!