One thing to look at is how Wynne's in-your-face endorsement of Trudeau did not have a negative effect on him during the Federal election, as many expected would be the case.
I think Wynne is unpopular, but people still support her despite the lack of popularity. Horwath for example, has the highest approval rating, yet the NDP has been reduced to third party status in both Provincial and Federal elections (being trounced in Ontario especially).
It continues to amaze me that the opposition hasn't been able to topple the Liberals in Ontario, considering the Liberals have handed them both elections on silver platters. Even in the Sudbury by-election, rife with scandal, the Liberals still managed to come out ahead. It's incredible.
Perhaps this is a case of sticking with the devil you know? Liberals benefiting from voter apathy?