Agree that Canon is likely phasing it out. I don't know of any cases where Canon has kept a camera in the lineup for long after its direct replacement has been announced. (Although they did seem to keep the 5DII for quite a while, but I think that was just an interim strategy until the 6D was announced, since the 5DII and 5DIII are significantly different cameras.)
I'm not sure, though, that it's correct to say the 60D is not selling well. The 60D body is still hanging in there at #9 on the Amazon best sellers chart, which is pretty impressive for a body that's been replaced. And, the refurbished store is now sold out of all 60D bodies and only has the 18-135 kit in stock.
Actually, its the 7D which doesn't seem to be selling all that well right now. It's barely in the top 50 of DSLRs on Amazon and the Canon refurbished store has more than 500 in stock. That may reflect that the 70D offers almost all the features of the 7D plus a few more, all at a slightly lower price while the 60D is selling at bargain basement prices right now.
The 7D has never sold well. It just doesn't fit in the marketplace that is stuffed with lower costing cameras. The best thing Canon can do in the future is to slim down it's DSLR line so that there are clear differences between the segments and to increase profitability by pushing the next generation of lenses in the retail markets.
That's absolutely not true. The 7D has been a very good seller for Canon. Does it match the volume of Rebels sold? Of course not. But, none of the enthusiast and professional cameras have ever come close to Rebels in sales.
The 7D has consistently been among the top sellers on Amazon since it was first announced. It is now four years old and still among the top 50 best selling DSLRs – no small accomplishment, especially as most buyers have been anticipating a replacement for a year now. Something which has undoubtedly cut into sales.
When it was introduced Canon clearly differentiated the 7D from other models in its lineup. Later, when the 60D was introduced, the differences between the 60D and the 7D were significant.
In order to upgrade the 60D Canon had to incorporate many of the features of the 7D into the 70D, or there would have been no reason for buyers to choose the 70D. So, today, 70D buyers are getting a camera with a marginally improved sensor and four-year old autofocus technology. If you shoot stills, the 7D is still a better choice, although not as much of a better choice as it was against the 60D.
This idea that the market cannot support a flagship APS-C body has been tossed around many times before on this forum, always without any evidence, information or research to support such statements.