Who would take over Ewing Oil if J.R. was removed as president? Remember, this was just after Bobby had made Ewing Oil so cash poor (liquid assets wise) while neglecting Pam for so long, and Jock and Bobby had bickered at that time too. Remember before J.R. was shot, he had sold 75% of those billionaire Southeast Asian wells to the hapless Cartel and Vaughn Leland, so huge liquid assets for Ewing Oil at the time that Bobby took over after J.R. was shot. I'm not surprised that Jock wouldn't get involved with that again so soon after the Bobby tenure as president of Ewing Oil. And remember that Jock made that "power is something you take!" statement to Bobby when Bobby was running Ewing Oil with fanatical determination and accused Jock of embezzlement. When J.R. got back in charge, with the Cartel still disliking him and Ewing Oil cash poor, he decided to finance a counter-revolution from his Swiss bank account to get the old Southeast Asian wells back to their original privatized owners.
The Leslie Stewart thing seemed interesting for a short time, but didn't really go anywhere in the end.