And I know Canon realizes this:
A 2006 DSLR is still very good still camera in most situations.
They’ve been lazy about introducing any serious mirrorless system.
Much of the world’s economy is still a big mess, because of the derivatives fiasco.
Better question: Why in 2015, if I were starting from scratch for digital, would I pick a Canon? There are two recent exciting cameras: The 7DII and the G7X–neither is without serious challengers. And the older 5DIII, 6D, and 70D all have serious competition.
Fuji, Samsung, Olympus, Sony, Panasonic, and even Nikon, Leica and Ricoh are significantly ahead of Canon in mirrorless. (Despite the prevailing attitude, the Nikon 1 system is a plenty serious, if too expensive, mirrorless line.)
Now there are reasons to pick Canon pro and prosumer video cameras, but those also have serious challengers.
Started out doing photography at the age of 6 using an uncle's old 1940 kodak brownie box camera. At 15 years of age, I decided to buy my very own 1975 Praktica SLR camera. I now shoot with a Nikon D850. I do unpaid TFP and commercial paid work.