AWS just introduced Kendra to do the same thing. They will likely suffer the same concerns. Google had a search appliance that I thought was a brilliant idea but never got much traction: https://en.wikipedia.org/wiki/Google_Search_Appliance
Google Search Appliance was used by thousands and thousands of big corporations - so to say it didn't get much traction is not correct. For many years it was the defacto solution for enterprise search solutions.
Huh, I basically never really heard of it being used. Guess that's the trick with 'enterprise solutions' outside of explicitly looking for it or it popping up on an aggregator like HN or /. (since this was starting in the mid '00s) you don't really hear about them.