Sony said on Tuesday that Mike Richards would immediately exit his job as the executive producer of “Jeopardy!,” completing a stunning downfall for a game-show impresario who just three weeks ago had secured one of the most coveted jobs in television as the replacement for the longtime host Alex Trebek.“We had hoped that when Mike stepped down from the host position at ‘Jeopardy!’ it would have minimized the disruption and internal difficulties we have all experienced these last few weeks,” a Sony executive, Suzanne Prete, wrote in a memo to staff on Tuesday. “That clearly has not happened.”Mr. …
