I remember seeing the Rotodyne at Farnborough when I was a schoolboy. Lots of aircraft were noisy then (wasn't that the point? Vulcan was felt rather than heard), but it was strikingly loud for a civil transport.
In retrospect it seems like an interesting approach to relatively high speed with VTOL, and mechanically simpler than the V-22. But I don't think we can blame its failure on political or managerial failure, otherwise somebody else would have resurrected the idea in the subsequent 60+ years. It's just like the flying car: sounds nice, in practice doesn't work out. Rail is the obvious competitor, and rail wins--even with security checks.
A few years ago I travelled by the excellent Spanish high speed train system: there were security checks, but they were non-intrusive and non-annoying; and the train was more comfortable than any aircraft I've flown in.