Of course. Because druids dont use normal tank items. You can use agility for tanking stats, no other tanks can now. You will never see a agility/dodge item come out now because it will be worthless to every class/spec except feral bear druid. Str provides a parry conversion for all other tanks.
Which has never happened before? Top guilds were selling t1/t2 in vanilla, SWP items were sold in BC, and ICC was sold in Wrath. Its got nothing to do with ease or difficulty of the items to acquire unless you make it take months to gear up and clear content entirely. 5 weeks after ZA came out on my server the bears were being sold for 10k per by multiple guilds. TK/SSC/BT and Hyjal were all run as gold selling runs by high end guilds where you paid 1-2k per item you wanted (or bidded if multiple wanted it aka GDKP).
Even already in cata, guilds/groups farm trash for BoE's and GDKP runs go into BoT and BWD regularly so your point is completely moot as its never been a problem previously.