[Klaus]

Oh, and the Pentax LX-1 was such a huge success... blew all the Nikon F2, F3 and Canon F1 just out of the bags of press-photogs, right?

Well, it's easy to call a camera a fail looking backwards, the question is was it a fail because of its concept or because of the brand name printed on it (and such being part of a bigger or in this case smaller ecosystem that maybe wasn't attractive enough).

Since you mention the F3 yourself: it had a modular design, too. 5 different viewfinders were available, combined with no less than 16 different focus screens, an optional motor drive, bigger film storage and different backs.

q.e.d.