So it turns out you were not alone. Getting people who did well on the quiz - whose parameters were trained on interview performance, by the way, so "did well on the quiz" was synonymous with "had a good shot at the interview" - to sign up for interviews was a major problem for a while.
The solution? We told them the first booking was just a "practice" interview. And then if they did well, surprise, it was a real interview all along. (If they didn't, we'd let them try again, though it almost never changed the outcome.) IIRC this like doubled booking rates overnight. I don't really plan to do this at Otherbranch (partly because being aggressively upfront about things is a founding value, even when it comes to white lies of that sort), but it's a fun story that I don't think was actually unethical.
There's a lot I could (do [1]) say about the psychology of interviewing, and it's something I'd love to write more about down the line. Mental health - especially around anxiety and depression - is my #1 personal cause and job hunting touches so concretely on so much of it.
[1] https://old.reddit.com/r/cscareerquestions/comments/1daumg4/...