John Bloor did a exemplary job with Triumph but I think the analogy with Continental and Lycoming isn't strong. In the case of the British motorcycle industry what they were making 40 years ago was non-engineered crap. The competition killed them with better function. Conversely modern aircraft engines are well engineered and work well, as pointed out by ZA, and they are not being put out of business by more technically advanced competition.
I agree that fuel and controls are the issues right now. I'm not a big fan of diesels but if anybody can produce a diesel that is practical with good 50 year life cycle cost, I'd say it would be Continental using the SMA design.