Really, how many people are printing at sizes that require higher MP? I understand that Canon has to compete with what others sell just to stay competitive, but that's because the consumer is buying their camera based on just MP. How many of you ever shot with a 1V, 3, 7/7E, or even a Rebel? Except for speed, AF, and weather sealing (OK the 1V offered a very primitive EXIF data), there was very little difference. What I am trying to say is that the resultant picture was usually just as good regardless of the body (not the lens though). I still have my 28-70, I have no plans on upgrading to the 24-70 much less anything that comes down the road.
Only when we do very large enlargements (bigger than 8x12, probably larger than 13x19) would we see a difference...and very few photo's get enlarged to that size. Frankly, I don't have the money to afford the framing for all the enlargements that I would like.
I'm sure the lenses Ansel Adams used would be considered vastly inferior by today's standard...but I'll take his photo's over mine anyday. Technique is worth far more than glass and sensors anyday.
And as a side note, on sharpness and landscapes. Lens sharpness is a moot point for any longer exposusers on a tripod, all it takes is a breeze, much less a gust, and sharpness goes out the window.
I agree with your sentiments regarding skill... with my clients, most portraits, the sizes range from 8x10's to 11x14... Keep in mind, even with the 7D at 300dpi it's native size only pumps out a 17.5"x11.5". While that's more than most people, and I know you can print at 240dpi and get slightly larger, it isn't as big as you would really think. I also have clients that like 2 page spreads and their magazines are roughly letter paper sized and so you are looking at about 11x17 right there, plus needing enough for a bleed. Lastly, on epsons you can get away with printing at lower DPI, however with commercial printers, they still require 300 DPI or they look crappy with the crappy CMYK color mode... As said before, I'd rather have the extra MP in my backpocket to shoot with as needed than need it and not have it. PS.... this last spring a company going to a tradeshow wanted a mural shot for their tradeshow booth... It was at 10 feet wide by 8 feet tall... I only needed to shoot it at 72dpi because of the printer they were using for the booth... with the 7d vertically, I was able to shoot the mural in 7 photos overlapping a little each time and used photoshop to quickly stitch them together... I was able to produce an image at their resolution and size that required no interpolation and fractal enlargement you would need if shot with a lesser camera.