We did have a problem of that kind with MC1 - then the grants were much larger and a smaller vote was required to win.
With MC2, the payments are quite small compared to the amount mined - for each 1 coin an exec gets, 95 coins are awarded to miners. There shouldn't be a problem with encumbency.
What we're seeing at the moment is just a very low voter participation rate - 5% is the highest turnout we have. I think it might be because MC1/Protoshares owners haven't claimed their coins yet, and it requires some education on how it all works.
It makes me think we need a HR officer to recruit candidates, and get owners voting.