The smooth operation of the Tory colossus has been a lifelong passion for thousands of Albertans. They run the riding associations, staff the campaigns, party together, marry each other, go crazy with joy when they win again.
Every Tory MLA is supported by a group like that. Leaving the gang that helped you get elected is an incredibly difficult thing to do.
The PC party will only be in real trouble, and MLAs could leave more readily, if riding workers themselves start sliding over to the Wildrose Alliance.
Braid considers it far more likely that rank and filers would abandon the Tory leader rather than the Tory party. The event to watch, therefore, is November's vote on Stelmach's performance as head of the Alberta Conservatives, not October's Wildrose Alliance Party leadership convention, which will (presumably) result in a victory by Danielle Smith.