A bit of a generalization easyswimmer and very much your opinion.
In fact some of CTC's output are people whose previous experience was 1000 (ish) hours instructing. I know because I fly with them. I also fly with people who have worked their way up from instructors to turboprop pilots and even heavy piston prop pilots. I fly with people who moved up through bush pilot jobs, survey pilots, helicopter pilots. Royal air force, Royal navy pilots who have changed career from various aircraft types. I also fly with pilots who were lucky and skillful enough to be sponsored through their professional licences and ratings.
CTC may be a good source of lowish houred pilots with good CRM skills, but they are not the be all and end all so don't kid yourself. "Getting safely down a procedural NDB to a safe landing " is no more important or relevant than many other aspects of the job either. The "skills you need to cut it on a jet" as you put it are learned through years of experience (many of them on that jet !) . Many if not most of those skills apply equally to other operating environments as well. Wait untill you have flown through some of the more remote parts of the world with little support and backup other than your own wits and those of your colleagues, before you pronounce anything about the skills to cut it on anything. I have flown jet airliners for the last 22 years and I can tell you that for the most part is it a comfortable shirt sleeve environment that is not terribly demanding in many respects. Given a CRT full colour Navigation display with raw data backup on my trusty 757 or a needle on the old F27 but with a second pair of eyes next to me, or a needle ,no spinning compass card, no autopilot, and just me on my lonesome on a light aircraft, all flying down your procedural NDB approach. Guess which order I would rather place myself in ? Actually I answered it for you.
Nothing wrong with instructors. Many of the good ones have very honed experience of being quick to detect adverse trends etc. they also should have developed good customer skills which they can adapt to CRM skills. Airlines directly and indirectly have long recognised this and employed pilots from this background. Clearly CTC have as well.