The field of candidates is huge. The delegates are apportioned proportionally. There's no clear frontrunner. The candidates and their top campaign staff know this and are not as likely to just drop out after the early states as in years past. This isn't like the Republican primaries in 2016, which were stacked for the frontrunner. Even our primaries in 2016, with just two candidates, left things open for quite awhile. Now we have way more serious candidates. Is anyone going to be able to get the delegates needed before the convention?