Reinhardt, we see things differently, based on different history, and experience, and that's perfectly fine, as long as each respects the other.
As you said, my experience and observation is opposite to yours, mine, and that of a number of Canadian and US test pilots I know, is exactly the meritocracy which Tester78 so aptly describes.
So candidates are not "chosen" ....
What we try to avoid is to have a XXX pilot with apparent good technical knowledge, to teach him to be a test pilot of the same XXX !
I was chosen. There's no other way to describe it. Transport Canada Aircraft Certification Engineers called upon me as a citizen, and then later as an Aircraft Certification Delegate of Transport Canada, to fly a number of aircraft for the purpose of confirming continued design compliance, following external modifications or alternate landing gear being installed. I did not request or apply for this role, I was asked, and agreed to fly. Interestingly, for one of those programs, I was the
only pilot TC could find within their available choices nationally, who had the required combination of skill experience and qualifications at the time. Happily, TC has since hired a very competent test pilot, who also has the required experience, and he and I have flown together a few times on program.
The TC request for me to fly was based upon my skill and experience flying this type of aircraft and or modification configuration. I was "taught" to be a test pilot for this purpose, by being told what to fly and evaluate, how to gather the data, and what information the report was to contain. So, a pilot with good technical knowledge was taught to be a test pilot.
followed by a flight in a type of aircraft exactly the opposite of the one on which they have experience (fighters pilots after minimum briefing will fly a transport type they will discover in the morning, and transport pilots will be seated in a fast jet cockpit..)
But there are more types than just jet transports and fast jets. And sub from that, there are unusual operations to be evaluated too. The modification might be
how the aircraft is being flown, more than the modification to it. (Parachute exit from GA aircraft, or deploying and recovering a towed object for example)
For myself, I have never flown a jet powered aircraft, and nothing in my career expectations suggest that I ever will. 30 years ago, when I was a very young part time sim tech for an airline, I had access to the DC-8-63 full motion but nearly no visual simulator we had. I taught myself to fly it late at night, after the real pilots had finished training. I read the flight manual, and with zero dual instruction just went "flying". I accumulated 45 hours of accident free flying in it, including a number of self induced emergencies. It was an airplane. What it had in common was that I would take off from a runway of suitable length, and return to that same runway. It was not particularly challenging.
When things get different is when the type of aircraft is other than a jet, and the thing you are doing with it is other than landing on that nice paved runway, or the aircraft is changing configuration in flight. I assure you that it is much more safe to take a competent pilot on type and operation, and ask him to gather flight test data, in accordance with a prepared and accepted flight test card, than it is to send a highly qualified engineer to fly a very different aircraft in a different environment. In the worst case, the non TP "pilot" will miss the test objective, and have to repeat the test to get the required data.
Sending a non qualified pilot, highly qualified "tester" (TP) out in a new plane could have needlessly high risks. I assure you that from my experience, a jet/mid to large transport pilot is going to have a seriously hard time flight testing a floatplane, flying boat, or taildragger on skis. These aircraft must be tested too, and the pilot doing it in accordance with an accepted test plan would seem to be a "test pilot".
So, flight testing is not a one size fits all. Pilots are not, and cannot be one pilot fits all aircraft types. Respecting Genghis' kindly provided definitions of a test pilot, the only thing that makes me think I am one, is that people keep asking me to flight test their aircraft, and the authority keeps approving the flight test plans, and accepting my reports in support of STC approval.
Other than that nuance, I'm just a pilot, with some flight test training, and 20 years experience, flying some really weird light aircraft. Attempting to include to exclude a pilot in the test flying world, may work if you are the person doing the hiring. Otherwise, your opinion is interesting information about your local environment, but has no affect on other jurisdictions. Whatever the DGAC chooses to do is fine with me, it's not my flying environment....