I think a lot of photographers get obsessed by their image sharpness, investing in expensive camera bodies and high end L lenses only to then look at shots at 100%+ and "see" softness.
A lack of sharpness can be down to many other factors other than AFMA - shutter speed, subject movement, ISO noise, out of focus, etc. can all impact on image sharpness.
I would say when I get an unsharp image it's usually down to my fault for not getting everything correct when I am shooting. My focusing is off or my shutter speed hasn't been fast enough to freeze any movement.
I would expect on a expensive body like the 5D3 that you should be able to put virtually any L glass onto it and get sharp results with no AFMA - unless the body or lens is faulty.
It was a worthwhile excercise for me to buy FoCal and calibrate my lenses as it has told me that my lenses are "Okay" quality wise as they only required slight AFMA and I now have an easy method for re-calibrating anc checking in the future.
FoCal does make it easy, especially as I have never done any AFMA before and I managed to calibrate all my lenses in just over an hour at first attempt.