The short answer is the Canadian electorate for the most part are totally mis-informed about the F-35 and continue to accept all the obsolete negative info about the jet (including way out of date pricing for the F-35 and false pricing on some alternatives). The anti-defence media (CBC, Toronto Star "Harper haters) continue to spoon BS to citizens who gladly eat this shit up hoping the money goes to their particular desires. The pollies, gutless as they are, are more than happy to defer or cancel important decisions for political advantage. This is not just a F-35 problem, it is a military procurement failure on all fronts.
From an economic POV, Canadian companies have done about 600-700 million on the JSF program and could manage another 10+ billion if 2500-3000 are built. A failure to procure F-35s by Canada puts that business at risk. Any other choice would not come close to this amount.