I wish it were so, but it's not. I usually start interviews with 5-10 minutes of talking about a previous project of the candidate, digging in to see how sophisticated the work was, how they solved problems, etc. I've had plenty of examples where someone bullshitted well enough to pretty much convince me that they knew what they were talking about, only to have it become clear in the more hands-on part of the interview that they couldn't possibly. I admit I'm not a great interviewer, so perhaps a really good interviewer could tease those things out, but I maintain that it's not always easy.

I think the usual situation is that the candidate was on a team where some impressive work was being done by others, understood it enough to talk about it in detail, but didn't actually do any of the challenging work themselves and couldn't work at that level consistently.

I'd like to think most people aren't actively lying or bullshitting, but it's easy enough to implicitly take credit for work done by a team when you're trying to sound impressive.