I've ridden a disc brake bike for two seasons already (never raced with it).
Am I impressed with ability to suddenly brake while commuting around the city in the rain? Yes, totally (despite, of course, locking the wheels in the process)
Am I impressed with the " stability" and "easiness" to work with the system? (in my case: hydraulic Ultegra Di2 6870). No, not at all. While I can get around basically any problem with any brand of rim brakes really quickly (and I've yet to have worn out a set of rim pads, not to speak about rims themselves), disc brakes have been much more finicky - pad changes at least twice per year, several visits to LBS for proper bleeding and lever adjustments (one of the most competent mechanics around, having worked for the local pro conti team). And this, ignoring the fact that you might have Shimano / SRAM bikes which need each their own bleeding kit, braking fluid etc etc. Or, if going abroad to ride into the mountains, I'm sure I can fix any problem with rim brakes. Totally not sure if that's the same if something happened with disc brakes.
Of course, this comparison of longevity is skewed due to the fact that I rarely ride my rim brake bikes in wet conditions.
So, would I like to have another disc bike? Yes, n+1 is absolutely the goal. However, for my training a disc bike won't add any benefit and will introduce maintenance complexities I'm not ready to commit yet. Although, if Cervelo came out with S5 disc next fall, I might rethink my position
For all the people who either do a lot of descending, have only a single do-it-all bike, do all the maintenance with their LBS, disc brakes are a more logical choice already. And, since overall the numbers probably add up as being the majority, we can answer the original question of the thread as "yes".