You might giggle and think that his name would have been so silly but you gotta admit that it would have sounded a lot more "German" than Hitler.
"Adolf Schnickelgruber" gives me the same kind of vibes as "Benedict Cumberbatch" and both are basically the most stereotypical name you can think of for their respective countries. (Yes, I know Hitler was from Austria, but the point still stands.)
So even though this "perfectly reliable internet fact" is usually given with a lame joke on how this name would have prevented the rise of the Nazi party I really have to disagree with that theory. I mean even if "Heil Schnickelgruber" doesn't roll of the tongue quite as easily we can easily see that despite his silly name Boodlebop Candlewax is still a highly successful actor. I mean, if foreigners can learn how to pronounce Eggs Benedict Crumblesnatch I see no reason why Germans themselves would not have been able to make Schnickelgruber into a serious name. Besides, it would have made Nazis even more dangerous since foreign spies would have been caught because they would have been unable to pronounce his name properly (or resist laughing while heiling.)
Honestly, I assume that even with a sillier name old Adolf would have had no more trouble being taken seriously than mister Buttermy Crumpetsquick.