I have a search tool / catalog of duckduckgo !bang operators https://mosermichael.github.io/duckduckbang/html/main.html - I am hoping that it allows for better discoverability of specialized search engines. The latest addition is a description for each search engine, just hover over the name, and you get a description derived from the sites meta and title tags.
I think that specialised search engines are gaining ground, it has become easier to set one up, thanks to elasticsearch/lucene. They can be quite good, for a limited domain, and they don't have to invade your privacy in order to find out what you are looking for. I think that what is missing are tools like this, that would aid the discovery and use of these search engines. I hope that this will allow them to eat into the market from the 'low end'.The projects source is here: https://github.com/mosermichael/duckduckbang
Unfortunately they don't invest too much into !bang operators at duckduckgo, however that's my input data...