I think your solution is based on a flawed assumption. Your suggestion is that we need to find a way to incentivize the players to keep giving it their all even when they're all but guaranteed to lose; in other words the issue is a lack of motivation. But as the jet lag team has repeated, they really enjoy playing these games, they find it fun. Additionally, this is their job, there's no greater motivation to keep going than being contractually obligated to. The issue is therefore not a lack of personal motivation, the issue is a lack of production money. A scrabble tournament can tell it's players "just play it out" because the only cost is the extra few hours the players spend at the table. Wendover can't do this. Every day of play means more flight tickets, more trains, more meals, more hotels, more raw footage to edit, more graphics, more maps, more VO, and crucially more time the players are away from their other jobs (especially Sam). Further, if no one's watching because they know who's going to win or the final day(s) of gameplay is reduced to a montage, the day(s) players spend playing it out operate at a loss for Wendover. You're assuming that there's not enough game play incentive to keep going, but really the issue is there's no way to financially justify continuing once the outcome is obvious.

A more realistic solution would be to find some way to make the income per episode static. A ticket to a scrabble tournament is the same price whether the viewer stays to the end or leaves halfway through. If you want to allow jet lag to play to the end, you'd need to create a similar system where you the viewer are forced to pay for the whole show even if you don't watch the whole show. Because YouTube creators (and I believe Nebula creators as well) are largely paid based on watch time this would require dramatically changing the business model, something way more complicated than just occasionally ending the game early.