I think you've nailed it. This L.A. Times article talks about the twenty years it took for Technicolor to really take from black and white:
Add to that that the oldest color film (very short, mind you, but most were) was in 1902, and you have a fifty-year adoption cycle from black-and-white to color.
Further, the statement, "I haven't yet encountered a director of photography who's genuinely enthusiastic about it." is meaningless in terms of the future of films (Historically, DOP's have far less power over such choices than directors and producers), but offers additional correlation: Very few, if any, DOPs successfully made the transition from B&W to color.* Most of the good color work came from a new generation.
* Take this as you will; I got this from a documentary about Wings of Desire, but can't seem to Google up supporting evidence just at the moment.