If I accidentally hired a guy like that, I'd consider him for a marketing position. :-)
This does seem to be the threat model many interview processes are meant to protect against though.
I understand there are costs involved in hiring then firing someone, but maybe that should be reserved as a way to deal with the most outlandish fakers and let the rest of us have a quick Google or two during coding screens.
But if you are lazy and prefers talking to people and watching videos, so you spend your day talking about these conferences with your colleagues rather than doing work then you have the scenario I'm talking about. It doesn't require some genius conman, basically any guy who prefers to talk about things instead of doing things will more or less fit this description. The degree they lack real skills depend on the degree they prefer talking over doing, but such people will always over perform at such interviews.
Lastly since the talkers get rejected by all the leetcoding firms, you will have an abundance of talkers that can't perform in the hiring pool. So the problem with talkers is way worse today than 20 years ago.
Often I feel like a con artist for doing this, especially if works to overcome a superficial interview. Sometimes it turns out my perception was correct and yet it turns into a better interview because I’m adding value to the interview where the interviewer had gaps…
You know how they made a program pass the Turing test? They didn't make it smart, they hardcoded a conversation where the program drove the conversation to where it wanted it to be. That way the person interacting with the program was passive, so they never noticed that they were just interacting with a stupid program in the 5 minutes they had with it.
The same happens in interviews, if you take a person who don't understand tech, but have watched a lot of conference talks and read some papers and he can re-tell those, and he even remembers answers to common questions from the question parts there, but he doesn't understand much at all of what was said he just remembers conversations, then that guy will look like a world class expert if he gets to drive the interview. But once he starts working he didn't know anything at all, he just learned to talk about these things not do them. Some would say "just dive deeper into his knowledge!", but you can't always do that, if you aren't an expert yourself in his subject area you wont be able to drive down deep enough to find his flaws, and since he is driving the conversation most likely you wont be an expert on what he is talking about.