Leica optics is just an investment to me. I am not really drawn to its optics per se. There's nothing special about it that distinguishes it from the likes of Zeiss. My favorite 35mm lenses are actually Sonnar lenses made by Zeiss.
Leica gears are the "cheapest" gears because you almost never need to spend a penny using them. Yes, you might need to put down $5K for a Summilux 35mm FLE but after using it for 2 years you would sell it at $6K. So the cost of owning it would just be interest on $5K - $1K which is negative.
Actually, your psychology adjusts once you into the Leica world. When I started with some cheap DSLR stuff, I thought $1K is a lot for a camera gear. But now, a $5,000 lens is pretty cheap to me.