"Trudeau won't live to see a balanced budget"
There are many factors that could see a balanced budget sooner than you think.  
First is the effect of the infrastructure investment bank.  No financial model has taken that into effect as no-one knows how to estimate its effect.  
Second, overhauling the tax system could increase revenues, especially if it moves toward taxing consumption rather than income.  
Third, taxing the capital gains on primary residences could be implemented so that those flipping residences, after a year or two, for profit would pay tax while those living in their primary residence for many years would not.  
Fourth, the government could reign in spending.  
Being in deficit until 2050 assumes no changes to taxes and no changes to spending.