AWK has inspired many other languages, as you've already mentioned. Why do you think this is?
What made AWK popular initially was its simplicity and the kinds of tasks it was built to do. It has a very simple programming model. The idea of pattern-action programming is very natural for people. We also made the language compatible with pipes in Unix....
Another advantage of AWK is that the language is stable. We haven't changed it since the mid-1980s. And there are also lots of other people who've implemented versions of AWK on different platforms such as Windows.
According to Aho, AWK is still one of the 30 most popular programming languages. Just a couple of weeks ago, I pulled out my copy of The AWK Progamming Langauge (wow! the book is much more expensive now) and wrote a 3-line program to generate a 5000-row CSV file of test data.
(Link via CodeProject.)