I don't think that's the case. Most of the expected value comes from the jackpot, and even if a large jackpot means you should expect to share with 1 or 2 other

I don't think that's the case. Most of the expected value comes from the jackpot, and even if a large jackpot means you should expect to share with 1 or 2 other winners, but the large jackpots are easily more than 3x the small ones.