Reply #9: I think a lot of the changes are due to the parties' awareness

[elperromagico]

of how a divided convention will look on TV.

The 1924 Democratic convention ran to 104 ballots before a compromise candidate was selected. Platform debates could drag on for hours as well. That's an extreme circumstance but it provides a good example of how intense the nomination process has gotten in the past.

Now, everything's cold and clinical. Conventions are essentially stage managed by the presumptive nominee to fit whatever message that nominee wants to present. It's dull TV but it fosters the image of party harmony.