It’s not comprehensive, but let me present a theory.
The modus operandi of the old ratfuckers was based on a particular view of the political world: That people thought things were mostly on the up-and-up, and wanted them to stay that way. Getting by on dirty tricks, they believed, was tricky—you had to be cunning, vigilant, prepared, and industrious, because you not only had to win—you had to appear to have won honestly.
The new class, meanwhile, holds the opposite view: along with much of the right, they’re convinced that nothing in politics is on the up-and-up. These are the people who think everything is a false-flag, or a conspiracy, or the work of shadowy leftist forces. They’ve heard for years, for example, that Democrats are getting away with murder on voter fraud, on spurious sex assault accusations, and the like—and they’ve thought most of the public was just too dumb to notice.
And so they decided, Hey, how hard could it be?