"Wes didnt drive this companies stock into the cess pit by himself he was helped by members of the Board." You bet.
One board member does not have the power to force such changes no matter who he is or what he has as his backing.
We all know that this board got rid of Nemis and sold off Windfall. Yes they also hired Wes so it can not be mostly his fault. (Sum nailed it "Basically people hire their own kind".) Wes's fault may be just not being the proper man for the circumstances.

Wes could have left due to inability to further comply with the board, a more likely scenario imho.