If I were wealthy (let us say the 1%) I would probably pay 10 times the price for double the quality, because at that level the value of money is not that great because one is oversupplied with it.
http://www.dxomark.com/Reviews/Leica-M-review-How-does-the-n...
That said, I really like the manual focus tabs on the lenses and the mechanism on the Q looks interesting. The Q is also newer so likely has a few improvements, but in general Leica has always been a bit behind the likes of Nikon, Sony, and Fuji in terms of electronics and firmware. Where they win is build quality.
Professionals are mostly likely to be more objective about what they need and are buying, if they view it as a tool (in my experience, at least).
another situation would be a serious hobbyist, that is to say taking photos is their main enjoyment away from work. They might be willing to spend a lot more even with small benefit.