Digital came in via DCPs which can carry lossless multichannel audio without compression codecs and thus there was no need for the systems any longer. Dolby went into visuals and invented their object based Atmos system. DTS sold the theatrical side to Datasat and they have their own new object system called DTS X.
DAD still has a great dynamic and fun mix. It's not too loud and is extremely enjoyable on DVD or Blu-ray. The old DVD also has a discrete surround rear encoded in it.