I think you're missing the fact that the mechanical watch industry is already post-apocalypse (i.e., the Quartz Crisis that started in the 70s).
The current mechanical watch industry does not exist for anything other than emotional reasons and won't see that much of an impact from another $400 electronic watch.
As a collector myself I think it's an interesting development for the industry and I'm sure I'll buy some version of the Apple Watch. I doubt it will replace one of my mechanicals as a daily wear.