I had also the same impression. I think one of the best approaches is let the best engineers at the company go through same interview process. If they can't get pass through the hiring bar of the company, then maybe that company should re-think their hiring process.
My current company has a very similar interview style, and I later learned that I was pretty close to not being hired because I didn't do quite as well as one interviewer wanted on a coding challenge: I ran out of time. But what I also learned is that the interviewer had never solved the problem in the language I used!
I had one of our most senior engineers, who has worked in this language's compiler, to try to solve the exercise. Instead of 40 minutes, it took him three hours!
If a candidate is going to interview in a language, for the love of god, have as a prereq that the interviewer is actually capable of doing the exercise in that language.
