That would be an interesting argument if the prices were somewhat comparable, but they're not. My M9 has lost more value since being new than the entire price of the RX1, and used 35/2 ASPHs are selling for about $1200 less than new, too. That's a $4K-5K loss in a few years. The RX1 is remarkably inexpensive for what it is.
Plenty of people still happily shoot 5+ year old 5Ds, D700s, 1Dsiiis, M8s, A900s, etc., and I don't see the RX1 as being any different. High IQ, full frame cameras tend to stick around a while.
Leica makes fantastic lenses, probably the best lineup top to bottom, but there are other capable lens makers. I think it's still all about the rangefinder. This rumored fixed zoom camera looks misguided, to me, especially if it is more expensive than the RX1.