the interviewer proceeded to ask me a deluge of very specific questions about said language, including implementation details of the language itself! all of the questions could have been looked up by an intelligent person online within minutes. and this was a well established, small, but well known company.
all of my software interviews can be summed up with two words: algorithm questions. but yet, my skills lie in architecture, writing bug free code, general design skills, testing, UI dev and client feedback, etc. none of these skills have never had the chance to be discussed in an interview. i came from another field and haven't spent a lot of time in the algorithm space. i can work through them as needed in interviews just as i do in a job, but that is rarely cared about in interviews. people want binary answers.
To my knowledge there is no proven way of finding out how talented one is except working with them for a while.
The best way to gauge ones skill level, IMO, is to observe how their code survives contact with the end user for a couple of years.
[1]: https://en.wikipedia.org/wiki/Pareto_principle In case you didn't know this but srs you're on hn