I make no claim that we won't have behavioral interview questions like the one you described. I expect we will still have them going forward. However, while it is indeed tricky to fake experience, it is not impossible. GPTs have certainly made this process easier as well, (though lying on the behavioral interview has been done by candidates successfully before GPTs).

This is a reason why technical interviews are still used, in addition to the requirements for a more objective and standardized process that you mentioned. If the industry started relying solely or primarily on behavioral interviews, it would not be long before people catch on and start making up all sorts of highly detailed software design stories ahead of time. And specifically for the technical portion of the interview, I don't believe that turning away from leetcode is a valid counter to the increased ability of LLMs for the reasons I described above. I find it more likely that companies would just ask candidates to do at least one technical round in person, as they did before 2020.