Don't be so quick to connect "expense" with "luxury", the two aren't connected at the hip. People think they are because this is the Walmart Era, where the ONLY thing to think about is price. If the commercial environment kills Leica it will be because their cameras are digital, not because they have coupled optical RFs. It just costs more to have Leica build something than Canon, et al, and the psychological life span of a digital camera is crap no matter who built it.
Wait for Nikon's new camera, possibly a digital FE2. Returning to past glories because they've run out of ideas to keep people buying. If they build a digital SP or S3, then Leica will sweat. Not because it has an optical RF but because it will be cheaper than Leica can/will build them. It will play out as it plays out. I have an M3 and an MP on order. There are thousands of Leicas on the used market; anyone who wants one will be able to get one. However, if one is addicted to the new well, these will be interesting times.
Cheers,
s-a