... few people possess his tenacity in the face of repeated setbacks.
This will be somewhat of a diversion from the actual aircraft discussion, but it vaguely applies.
Steven Levitt (he of "Freakonomics" fame) has stated numerous times that quitting can be substantially more beneficial than persisting in the face of failure. Obviously not all the time - witness how successful the cold fusion folks have been over the past 60 years by persisting (that's a joke, son). But sometimes, it's better to quit than to persist.
Now, with respect to tenacity, there was a guy who bought a heavily modified COZY (modified to be a twin, and have a custom fiberglass/carbon spar and wings) against all recommendations NOT to buy it. And then he spend the next few years, driving two hours each way from his apartment in Manhattan to the airport out on Long Island, to work on the plane, replacing the spar and wings, removing the twin engines and installing an O-540, and installing a forward hinged canopy. At every stage of his work, he was dissuaded from moving forward due to his lack of knowledge and skill, but everyone that talked to him (and I spent a LOT of time trading email with him, trying to keep him on a safe track) tried to help him be safe. He would listen, nod his head as if he understood all the good advice he was getting (and he did get good advice, not just from me) and then almost always do the opposite of what he was told.
Eventually, he got the plane flying, and although he was told (by me) not to do ANY stall testing until we figured out the CG questions the plane still had, and until he installed the leading edge vortilons that you see on most canard aircraft, in July, 2014, he managed to get the plane into a deep stall over the Long Island sound. That would have been OK - all other right side up deep stalls in canards have been survivable, but he was an aerobatic pilot, was wearing a parachute, and pulled the pull-pin on the canopy hinge ejection mechanism. The canopy came backwards and he died where he sat from blunt force trauma - not from the impact with the sound or from drowning.
In this case, his tenacity (and he was the most tenacious guy - and a NICE guy that I ever met), in the face of good advice to the contrary, killed him. It was very sad for the canard community.
Long story - maybe means something in context...