In general, doctors use very low end microscopes... if at all. Now lab technicians.... they have decent gear... but if you really want to see the good stuff go to a physics lab for a scanning tunneling electron microscope so you can see those individual atoms...
A real "pro" goes for the gear that get's the job done, not the very best. A doctor in a fertility clinic is not going to get the very best.... they want to watch how the sperm moves, not kill it and check to see if all the atoms are in the right place
So are you saying that there is no such thing as "pro grade gear"?
My point is that there is, and it is up to the manufacturer to label it as such.
The 1D X is obviously a pro camera, especially for sports shooters. The 400 f/2.8 ii is also a pro lens. Is it only bought by individual pros? No, agencies, publishing houses, enthusiasts and those that want the best purchase it too.
Does it fit every pros needs? No, but that does not make it any less pro-grade.
If a pro sport shooter sits on the sidelines and shoots pictures with his Samsung Galaxy Note 3 are you seriously suggesting that that phone is a pro piece of photographic kit?
You may say that is a bad example, but would you say that if the guy was using a 5D Mark III because he could not afford the 1D X? But if so, what if you can't afford the 5D Mark III or even II, but you can afford the Samsung Galaxy Note III which double up as a phone when you are not shooting.........
To say that it is the operator which makes his or her tool a pro grade piece of kit is ludicrous in my mind. But it is not a big deal, it is just my humble opinion.