It is funny, for all the histrionics that these threads throw out, the highest level pros are still using Canon cameras and 24-70 f2.8 MkI's, just today I came across this video of Patrick Demarchelier shooting Beyoncé for Vouge
Behind the Scenes Beyoncés March 2013 Vogue Shoot Small | Large
Or look at any of a multitude of videos of Annie Liebowitz,
Behind the Scenes: Meryl Streep by Annie Leibovitz for Vogue US January 2012 Small | Large
that show her happily working successfully for the high end of the photo industry with her faithful 1Ds MkIII's and, again, the 24-70 f2.8 MkI.
I got in several disagreements over the "upgrade" the MkII 24-70 gave, these people have more money than God yet they are more than happy with the quality they are getting from "outdated, outclassed, second rate" gear, well if they can do it with what they have surely we should look to ourselves a little if we can't regularly get exposure to within two stops of normal.
In too many instances increased camera capabilities are used as an excuse, by people with ever lower photographic capabilities, for their inadequacies. Rule 1 get your exposure right, rule 101 for RAW shooting Canon users, ETTR
thats because Subject > Quality of Light > Gear. (i could be swayed to put QoL first but i did this order because Leibovitz is renown for her handling Subject matter above all else)