The high water mark of that was 2016. But part of why is the party not only saw what had happened to the GOP in the 2010s, but also had already dealt with a similar insurgency with the McGovern campaign.
Ironically, the GOP primary process was much more democratic at that point, because the Dems had already given themselves tools to shut down a base revolt, like superdelegates, etc.
sorry, let me correct that - the current heightened state of open genocide