The way the primaries are set up, along with the modern political process, someone will gain momentum, and there will a winner by convention time.

This is assuming no candidate breaks the DGLB rule.

I watched my first set of televised conventions in 1956. The broadcast people were constantly hyping democrat floor fights (Ike was a given), and the nomination coming down to the floor.

I loved that stuff, it seemed exciting like waiting for a storm, dangerous, unpredictable, a name never heard before. I was glued to the TV, from gavel to gavel.

By the time I watched my second set of conventions, I had figured out that it was 99% about boosting network ratings and early seeds of cynicism were planted. :)

To the best of my recollection the tooth and nail conventions had happened, but no more than once or twice in the early 20th century. This is not to say that candidates were not chosen by machine politics until the national primary system was implemented. It was just done peacefully well before the conventions.