In other words, it's more reason to pay attention to trends in sales figures and changes in the competitive landscape as opposed to the current market snapshot.
Up to end of 2011, Canon hardly lost any market shares worldwide.
"In the market for cameras with interchangeable lens, or single lens reflex cameras, Canon controlled 44.5 percent of the market, followed by Nikon with 29.8 percent"
Thom Hogan (bythom.com) translated Nikon's sale of 4.7 million interchangeable lens cameras in 2011 as 31% market share. This means Canon's sale of 7.2 million interchangeable lens cameras has a market share of 47.5%. So, little changed from 2010 to 2011.
We'll see what happens in 2012.
We should keep in mind having the latest and best technology does not EQUATE to survival. Olympus, Panasonic and Sony are all bleeding very badly... not in the photographic business, but when overall financials are considered. Currently, Canon's only worthy competitor is Nikon.