Yeltsin wasn't born rich, nor was he a particularly convincing social force.
I see a specific combination of factors that propelled Trump into power: immense inherited wealth, being spoiled and myopic as a result of said wealth, the profound influence of mass media and spectacle, and a populace that is facing downward mobility or some sort of societal decline.
A lot of possible comparisons are career military figures, but Trump never got his boots muddy in anything like the military.
One comparison that I often like to make (which pisses off the libs) is George Washington. Fabulous wealth that he did not "build up" himself, profound racism and classism, reactionary politics, marshaling a contingency of landowners and petit bourgeois to become the dominant political force. The biggest difference was that Washington was more literate and tacit and proper, while Trump is a showman who dives into every intrigue and controversy.

