Just chiming in with the proper meaning of "egregore": For something to be an egregore implies that a group (usually large) believes in and recognizes the presence and the power of this specific thoughtform. Popular curses (the Great Bambino, mummy curses, for example) or legends can become egregores, but a single man wishing to do so is just strange, going by the definition of the word.
An egregore is a thoughtform, not something of flesh and blood. When you raise a living thing to the height of a god you do it in much the same manner an egregore is created, but there is a different word for it: apotheosis. (also, it should be noted that an egregore is usually thought to be under a god in terms of power, so it's a strange comparison)
The way I see it is that a living person wouldn't attain godhood until long after they were dead. Simply because the physical body doesn't live long enough. And being dead kinda guarantees you can't mess up ;)
For example, Emperor Hirohito: the Japanese emperors were thought to be direct descendants of the gods, but when WW2 ended, Hirohito had to bow to General MacArthur and the Japanese people were going nuts... it showed that he was indeed human. Or a more popular reference: at the end of 300 when Leonidas throws the spear and makes the "god king" Xerces bleed, proving his mortality.
Hitler definitely had influence over people, but I wouldn't say it was just him directly. I'd say a large part of his influence is owed to his SS. Interestingly, Hitler was a big fan of the occult -- but in the end no fear or magick could save him. He's idolized today among Neo-Nazi groups, and The History Channel is jokingly called The Hitler Channel (at least here in the US), but I don't think there many people fearing any supernatural god-like influence from him today. Coincidentally, I just saw an advertisement for a Ghost Hunters episode where they are looking for Hitler, lol.
A sigil can help magnify your power, but that alone isn't enough. If becoming a god were this easy, then everyone would be trying it. Sigils are just one technique for influencing your surroundings, manifesting things, etc, but they're no more powerful/effective than the person using them.
