Hmmm, interesting. I do agree with you about the fact that film makers should have wanted for the Digital Video technology to catch-up with film's resolution. I think there is also the issue of Digital's ability to be as dynamic with the colour palette. It is very good(especially comparing to old broadcast video), but I don't think it is quite as strong as companies like Sony make out.
I have seen a film in 8K digital(Django Unchained) and it seem pretty good.
I do recall the big fuss being made of DLP. I saw 'Finding Nemo' at the Odeon Leicester Square with it. That looked amazing, but having a CGI film to DLP makes sense. No loss of quality.
DV can't do 70 mm film properly - yet. Although, there isn't really that much call for it. I suppose only for special IMAX films it was needed.
I have only ever seen one 70 mm film projected (The Master). It did seem that epic. Probably because of the cinema it was shown in(The Odeon West End) and also because of the way the film was shot with the framing. It mostly looked like a slightly wider 35 mm film, but not by much.
I suppose that it does sort of make sense to go digital. Ease of use with the media, etc. Plus, not having the problem of print damage and degradation.