Are there inherent problems with 802.1aq preventing wider adoption?

Outside perhaps Extreme (Avaya) Networks and Alcatel-Lucent hardware level support for this protocol seems pretty rare. And there is no linux kernel level support that it can see either beyond the three year old and seemingly unmaintained PBBR code.

I don't quite understand this because it would seem a fully meshed network with no blocked ports and super fast convergence time is pretty much the holy grail of networking. I assume I"m not the only person who sees 50% of their network infrastructure sitting unused and wonders why we aren't feverishly working to solve this waste of resources. So why isn't 802.1AQ (Shortest Path Bridging) more prevalent in data centers and product offerings?

• Have we found insurmountable problems in the protocol?
• Have we found something better since the IEEE approved the standard in 2012?
• Or <insert your own conspiracy theory here>?