Very good discussion, and as my perspective is limited, I'll only offer a thought I don't think was covered above.
As is well-documented, in the past many manufacturers used ebauches from outside suppliers and then modified or finished them to unique standards. Many of these vintage watches today are highly desired and their lack of a true in-house movement is at most a quirk or afterthought. The Vacheron Constantin Chronometer Royal was originally a JLC ebauche, wasn't it? No afficianado minded this then or now.
Perhaps the problem is the lack both a variety of ebauches and their perceived quality. If the only choices are 7750, 2892, 2824, 7001, and 6497/8, then it's understandable why collectors would want something different at the heart (or the start) of their watch.
But imagine that the JLC 875 autotractor was available for purchase. Or the IWC 80110. Or GO 100. Imagine Zenith remanufactured caI 135 and sold ebauche kits. I think then perhaps watchmakers would be happier promoting the starting materials (witness the Voutilainen/Peseux 260 story) and would also perhaps have a movement better suited to their vision, rather than subjecting the usual suspects to the proverbial Procrustean bed.
I could argue here that a new economic model is needed. If manufacturers don't sell ebauches, then I would say they aren't priced properly. A question for independent watchmakers: If you want to start with an JLC 875, then what would you pay for it? The watchmaker can then ask the collector: if my new watches started with the JLC, how much would you pay over the same watch which started with a 2824?
Tom