It also appears that Bernie's core support is smaller than anticipated and not just because of other candidates. In 2016, Bernie was the place to go in the primaries for any anti-Hillary Democrat. He received 61% in NH in 2016, but less than half of that this time.
If that is so, the DNC doesn't even need to rig the election like in 2016. Bernie will just have his core 25% and that is it.
Also, he might not dominate in NV as expected. The Culinary Union, the most powerful NV union, has been pushing against Medicare for All. The union has its own Cadillac plan paid for by the casinos and doesn't want to give it up. Plus, the NV unions, though very powerful in the Democratic Party, are largely captive unions controlled by the casinos. The casinos don't want Bernie, as they are more integrated into Wall Street than ever before.
If the union members turn on Bernie, NV will likely be a mess with no clear winner, like the first 2.