Analog electronics is basically only used nowadays when digital literally cannot accomplish the task (RF, SERDES, ADC/DAC). I haven't seen any asynchronous designs that can do things sync designs can't do, just that claim to be better by some metric. Until now, process improvements have made these benefits of async design not worth the additional design effort.

I agree that async design is worth researching, but there is a good reason that undergrad level digital design assumes sync.

The game may change going forward since Dennard scaling is dead. 'deepnotderp probably has some interesting insights on this topic, perhaps he will chime in.