From reading a lot of mailing list and bugzilla posts I get the impression that they do care about Macs but the current (very old) renderer is just never going to play nicely with MacOS without a major overhaul, and that major overhaul is Webrender which has been in development for several years but has yet to land in stable because writing a new renderer is just a really large undertaking. Webrender and planeshift should bring a pretty huge performance and power efficiency improvement when they finally land in stable.