@jrista – You state that Canon's sensors haven't improved since before the 7D, and that all of their competitors' sensors have substantially improved, that Canon's customers have been demanding improved sensor IQ, and that Canon 'must respond'.
A small fraction of the market shoots RAW, a tiny fraction makes large prints, and an infinitesimally miniscule fraction even knows what a Stouffer step wedge is, let alone has one.
Small wonder this 'sensor IQ gap' has no impact on sales. The bottom line is that for the needs of the vast majority of dSLR buyers, the IQ delivered by Canon's current sensors is more than sufficient, and that's not likely to change any time soon.
But a fair percentage of buyers pay attention to online reviews. Neuro, I'm in nearly 100% agreement with you on your contention that sales tell the story. However, it's dangerous (as IBM, Intel and Microsoft discovered several times, and as Apple may soon discover) to assume that what worked in business for so long will continue indefinitely. It's a reasonable assumption that if the I.Q. gap gets wide enough, the popular press, review sites, and entities like Cons. Rep. will start to disregard Canon's whizzbang features and marketing prowess, and view Canon's lineup as unworthy of serious consideration. You're correct that this will not likely happen soon (e.g. in the next 2-3 years), but 5 years is not out of the question.
IBM, Intel and Microsoft may have had episodes where they badly misunderstood the market, but they were able to recover due to their deep pockets and a willingness to part with previous strategies. I believe Canon can do the same. Based on Canon's (corporate) track record, I'll bet they have the ability to deliver IQ equal to or exceeding what's on the market now, but they won't do so until market conditions force them. Eventually, as jrista points out, the market will force them.
One more thing: you should know by now that jrista is not a DRone. When he makes assertions he almost always has good reasons for them, and he's willing to talk things out and admit his errors. You may disagree with him, but try asking politely for citations rather than descend into name-calling.