BBC Radio (and NPR) laid the template. Slow and steady quiz questions, host reads out the score at the round break. I think Double Dare '76 is about as much complication as an audio only format could absorb--Millionaire is a could, but part of the excitement is lost in not seeing the reactions.
Part of the allure of Password and Pyramid is that the home audience is let in on the secret to be divined. (Does the in-house crowd know/can they see it from a monitor?)