Indeed, Jeopardy has existed as an audio-only entity, via its J6 game which Amazon Alexa used to offer as a subscription service. It essentially took the unused clues from actual recent categories.
And believe it or not, Wheel of Fortune was actually attempted as a radio game from the prolific mind of Mark Richards, aka Alex Trebek's "best friend", who hosted a drive time "radio game show" for XTRA 690 out of San Diego in the late 80s. He actually instructed players who phoned in to write down the blanks in the puzzle and number them. One shudders to think if car phones were more prevalent at the time how many accidents he might have caused.