According to the book: “Cierva Autogiros” by Peter W. Brooks, about 35,000 hours had been flown during the development of the Autogiro when the first fatality occurred.
It is important to note that Cierva was a brilliant engineer who did not compromise sound engineering principles during the experimental phase; he stayed with CLT and centered the tail surfaces in the propeller slipstream in order to compensate for propeller torque reaction and yaw due to the rotating propeller slip stream.
Not one modern gyro conforms to Cierva standards; the Dominator came the closest. But I suppose that if modern gyros looked like a Cierva machine, they wouldn’t sell. We all like that low slung Italian sport car look.
I need to get a scanner that works with Linux; I have a W7 computer that works with my old scanner but it is messed up.
Couple of things as a follow on and I don't know the answer but merely rhetorical. When Cierva's aircraft were "current" the environment was likely different. Were those able to fly more air minded? Certainly the instructors of his own flying school [Alan Marsh and Reginald Brie] have far richer aviation CV's than anyone I know currently instructing in the UK for example.
You also had airfields which were just that - fields - so landing into wind was no challenge.
The aircraft themselves are incomparable really. The popular Cierva C30 was over 30% heavier than an equivalent modern gyro and c.30% bigger rotors, which were fundamentally different to the 2 blade teeter type of today. With the aircraft being of a magnitude larger than the aircraft of today are environmental effects reduced.
I'm not sure the looks of a C30 make it unsaleable as much as the above wouldn't fit many countries regulation for light gyroplanes. As for the Dominator. I'd buy one today but I live in the UK and so I couldn't fly it, so that becomes a major barrier and that becomes a big sticking point.
We can scoff, deride aircraft as "Euro" tubs. We can suggest Fetters made a low slung aircraft that made many smoking holes BUT they were all in the market. ELA, Dominator, AirGyro [and similar], American Ranger, American Autogyro, Sportcopter. We can't fly any of them and engineering wise BCAR-T is well documented [it may have some items that are superfluous or ill conceived but that shouldn't be a barrier to an aircraft claimed to be superior to those that do conform] and where is everyone? In a way its like the moan up about gyro glider or hand starting rotors and feeling your way into the air. We would all like to feel the fibres in that fabric but at the end of 2020 its just more peanuts being thrown out of the gallery.