And now suddenly it seems that a host of new programming languages have appeared

That’s your perception of course, but I think new programming languages have always been appearing. The thing is that the old ones do not necessarily disappear, so there’s a cumulative effect.

I was looking for a graphical representation, but this wikipedia article shows it better imho. I didn’t count, but it doesn’t look to me like the last 2 decades are overpopulated.