I agree with most of what you wrote about the special place that PP occupies. And I don't want to reduce the discussion down to pure semantics. But in my opinion the connection between the ability of PP to service vintage watches and it's slogan is tenuous. The idea that I get from those adds is that any PP watch is so special that one should think of it as a family heirloom.
Also let me point out that although PP is indeed capable of servicing and maintaining all the watches that they have ever made they have little desire to do so except for very special cases. I have seen completely insane service quotes for very basic pocket watches in great condition. This is pretty much equivalent to refusing service.
As for RM, my intuition tells me that they won't be around in the long term. But does that really matter? It is a brand that relies 90% on the marketing genius of Richard Mille. Not that there is no interesting stuff in the design and approach to watchmaking, but it is not the key. RM is all about instant gratification and what he said just enforces that notion. I am personally not bothered by it, at least his message is consistent.