Here's the thing: HD sprite-based graphics are very, very expensive nowadays. Most devs have shifted to 3D now since it has become more viable budget-wise. Sure, when we look at Lab Zero's games (Skullgirls, Indivisible) they look pretty, but I'm pretty sure they're bleeding from their pockets doing that kind of graphics. That, or they got a one-in-a-million deal with their animators.