They don't care and think 5d3 sensor is fine
They will run some marketing campaign admitting to mistake and offer some solution for future.
They will try to get next sensors from Sony as Nikon did
They will try to get sensors from another company than Sony because of some Nikon exclusive agreements
Not going to happen.
They didn't make a mistake, they knew exactly what they were doing.
They will never buy from Sony or Nikon, that's the worst thing for you, for me, for competition, and for the industry in general. Rewind a few years, and imagine that Canon bought Sony sensors too. The 5D2 wouldn't exist. The 1Ds3 wouldn't exist. The 7D/60D/550D/600D wouldn't exist. We'd all be stuck using the same 12MP D300/D700 sensors. The new 24MP NEX-7/D3200 sensor wouldn't exist either, without the competition from the 5D3 and 7D sensor, there's no incentive to go any better.
They will care a S___ and listen to pros who actually use cameras out in the field.
5D3 was what happened when they listened to the Pros.
The Pros they listened to were event photographers, wedding photographers, people whose livelihoods depend on being able to focus accurately in low light, being able to take the least noisy shots possible in low-light, silently from the back of the church or on a dimly lit stage.
They will run some marketing campaign to defend the results achieved with current 5d3 sensor
They don't have to.
As said, it works perfectly well for its intended audience.
They will work harder to get better results and follow the path they do now
The 1DX and 5D3 were both releases aimed exactly at target markets. The 1DX target market is for photojournalists who *must* get a shot, and *must* get it to the publishers (paper or 'net) ASAP, or they're out of a job. Hence the best Canon AF ever, the 12/14 fps, the ethernet port.
5D3 was aimed at the wedding photogs who can't afford the 1DX, who need silent shutter, who have to carry the damn thing all day and don't want a gripped body or need the best sealing.
The Pros they haven't listened to lately are the wildlife/birders, who are almost always focal-length limited, need more pixels-on-target, need f/8 focussing. The 1Dmk4 is still the camera for them. Will the 1D4 be replaced soon, in a 3D or 7D2 with more MP-on-target, and f/8 focussing?
They also haven't listened to Landscapers lately. They are the ones most disappointed by the 5D3 and the ones most likely to switch to the D800. They need the Low-ISO Dynamic Range that canon just isn't giving them. They need the Megapixels. They don't need ISO6400 performance.
Will they introduce a 30-40MP+ 1Ds/2/3/4D body to make landscapers happy?
With both of those segments, there's a *lot* less market share than for the photojournalist and wedding/event photographers that were targetted by the 1DX and 5D3 bodies. So maybe Canon will just ignore birders and landscapers forever, and continue on their path of most-market-share? I hope not, but they're going to be fine and making enough money from the 1DX and 5D3 bodies to not care.