I meant to say "what would it take for people to think of Prolog as a great general-purpose language?".
I have never used Prolog for anything serious, but I think it has great potential and I really want to like it. It almost looks like the perfect programming model, and I want to understand why it's not.
What you're asking is something that the logic programming community has asked itself very often, but it's very hard to answer with any certainty.
One thing that should be noted is that Prolog was very popular, for a brief period of time, in the 1980's. For instance, check out this year's TIOBE index report:
If you scroll down to the section titled "Very Long Term History" you'll see Prolog listed as the 3d most popular language in 1987 (behind Lisp in second place and C in first, and before C++ in fourth). By 1992, it had dropped to 14th place and then it was pretty much all downhill from there.
As a personal anecdote, I've read a number of Prolog texbtooks from the late '80s and early '90s that begin with saying that it is very important to learn Prolog because it is sure to become a very popular language in the future.
In other words, Prolog did have its time in the sun. But then it fell from grace.
As far as I can tell, the most likely narrative to explain this meteoric change in fortunes is the one that pins the blame on the association of Prolog and logic programming to the Japanese Fifth Generation Computer project. This (theoretical) explanation of the rise and fall in popularity of Prolog is proposed here:
In short, how this story goes is that, when Japan chose to use logic programming for its Fifth Generation Computer project, which was seen as potentially extremely disruptive by the West, companies and academics in Europe and the USA suddendly took a great interest in Prolog, thinking that the Japanese must know something they didn't. Then, when the Japanese project flopped, it took Prolog with it.
I stress again it's just a theory, but, to me in any case, it's at least very plausible.
I have never used Prolog for anything serious, but I think it has great potential and I really want to like it. It almost looks like the perfect programming model, and I want to understand why it's not.