on a more positive note, I saw it recently re-pointed out that the Democrats primary setup is not well conditioned for tons of candidates because of the 15% cut-off*. As a hypothetical, if Biden tanks under it, while nobody else rises over 15% across the board, Bernie's near locked-in ~25% could (like Trump similarly watched all his opponents box themselves out) win majorities of delegates with some pretty low vote counts through the two sweetest words in the English language: default.
while the current media-campaign system, which Trump similarly used to his advantage, means you can run a shoestring campaign for far longer off just free media and the debates with little reason to drop out before Super Tuesday in case you catch temporary fire (is not guaranteed to work even if you run an ad proclaiming your eventual convention victory like Kasich) especially if most of your campaign is Twitter and media profiles and standing on things anyway
i'm sure there's probably a old bylaw that allows the party to force all these young white dudes to fight Amy Klobuchar for the right to remain in the race
*only one candidate has to exceed 15% to claim all of the delegates in Democratic Primaries, anyone below 15% gets nothing
edit: the GOP finally took away some of these rules from the states last cycle (they used to let the states decide everything) and tried to create a system in which >1% = 1 delegate (best as possible if there were enough delegates) with some "traditional exceptions" through Super Tuesday and then the thresholds started increasing and eventually included winner-take-all states...this was why Trump's delegate lead got more insurmountable even though his % didn't go up too much above 40% until everyone dropped out...it worked pretty much as the party elites intended to force a slow coalescence around the lead candidate except for that whole thing with who that lead guy was