[falsissime]

> ... all the activity of the early years of logic programming has died out, ...

Of course, now there is activity of the current years! What else could we have now? If you look back, there was not only progress but also quite a lot of regress. Like, dif/2 in Prolog 0, then to stay submerged for so long, resurfacing in Prolog II and Mu etc. Errors in Prolog I, then abolished in DEC10 at the expense of incorrectness, only to resurface later on, but still not entirely recovered...