It was said that Canon did not issue 24-70 f/2.8 IS version as it would be bulky and IQ would be worse (or lens diameter size would have to be wider than 82 mm). Current Tamron 24-70 version has IS and IQ is slightly worse than Canon's 24-70 MkII version. Also, Tamron price is significantly lower. What I currently see in the market that Sigma and Tamron significantly improved quality and we see INNOVATIONS in these companies. On opposite side, Canon makes only slight updates and puts significant price cap on their products. What is my biggest fear that Canon might adapt Apple strategy, to release "new" product which is substantialy the same as old one and expect that loyal fans will buy their products. I would understand if Canon realeases 24-70 1.8 IS version and charges much more money than competitors.
Canon was sleeping when mirrorless cameras were evolving, current P&S market is sqeezing, very strong competition in DSLR lenses is increasing. If the same trends follow in few years we will see that Canon produces DSLR cameras only (lenses will be bought from Tamron and Sigma). We really need innovative products for reasonable price from Canon!
I think you need to take a long and pragmatic look at how Canon have reacted in the past. Canon took a few years before they build their fisrt few DSLR models. But they took their time, watched not just how the market developed but also how the technology developed too. They chose CMOS where everyone else was claiming CCD superiority....Canon stuck to their beliefs and were proved very right.
Canon make a lot more money on it's lenses than it's camera bodies, but it takes years of careful development to get a lens right. Rushed products like the 50mm f1.2 L and 1DmkIV caused marketing nightmares for Canon, which Canon were wise to learn from. Canon has a 5 and 10 year plan, to which most of us are not privvy to. Sometimes they don't get everything right, but the general trend is that they really know their market and what their customers need (not want).
Canon's L lenses generally have at least a 10 year life span, that's a lot longer than many other brands. For example, take a look at how many ef 70-200mm f2.8 L IS there have been, 2. Now go and compare how many Sigma have pushed out, it's a lot higher. Canon like to get things right first time and keep their products in production for as long as possible. This jacks up the initial price up a lot but they discount very quickly (2-3 years later). In the current cameras, at the top end the 6D, 5DIII and 1DX have no real competitors....again they are state of the Art. Their crop cameras are currently going through a renewal (70D/7DmkII) to bring them back to the top again. Canon's white lenses have no equal, in performance, weight, features and IQ. Their TS-e lenses are the most comprehensive and optically strongest on the market. They offer more macro options than any other brand, the 100mm macro L IS is an amazing performer. Their range of fast primes are the envy of every other brand and are generally better than anything else out there...bar a few lenses which are in the process of renewal. Canon's f4 range of lenses are regarded as some of the finest zooms ever made and again are unmatched in the market place.
When I look at the new 24-70IIL, I can see a lot of devepment for long term Professional use...which I really doubt that the Tamron will cope with. It's AF is far superior, it's more robust, it's certainly has stronger IQ.
Not everyone wants a mirrorless camera, it's a niche item. Canon have a nice product in that range but it's not the tail which wags the dogs head. Olympus and Fuji might be going down the whole "misty eyed retro" look at the moment, but their products are seriously flawed in so many areas.
So just because Tamron put an IS unit in their 24-70, you think Canon don't innovate anymore? I think you need to get a wider perspective my friend.