Already Twitter is full of conspiracy theories that the vote was rigged because they can't fathom why shareholders would vote for the status quo.
Here's the thing: shareholders don't like the status quo (given the current stock price drop), but they really don't like the "change" the opposition...
I think investors were thinking this would be a close race given how Peltz's runs on P&G (which he won) and DuPont (which he lost) were very close. This was a landslide loss by activist standards.
He could've had a chance if he didn't start complaining about all-black and all-female casts in Marvel movies. All that did was make him out as an angry grandpa nostalgic for the 50s.