One thing is for sure ... analog synths have no hope of emulating what todays digital synths can do.
Well there will come a time where digital OCS have catched up, so for right now digitally controlled analogue synths is the best to offer.
How long it will take before analog synths become pointless we can only speculate.. but considering the complex nature of electricity and its behavior you need kind of cpu hungry algorithms for that to make it sound trustworthy.
I think Digital synths are best for some stuff and analog is without question best for some stuff.
But for ambient music and Pads analogue synths tend to have the most advanced timbres to work with while digital OSC in micro-detail can appear kind of dead and boring without any interesting harmonics which make it sound alive.
I will not be as optimistic with the time table how long it take for digital to catch up.
i would say maybe 15-20 years.
Anyway I am not the guy to ditch digital but we need to give it proper time to develop..