In actual fact, under PR the Liberals would never form a majority government (the only 2 governments in the past 60 years that would under PR form a majority were Dief in 1958 and Mulroney in 1984) and the Conservatives might occasionally do the trick.

Justin and The Butts Kissers never wanted PR.  They wanted a ranked/preferential ballot system because it would ensure them of perpetual power and give the Liberals a de facto dictatorship like the ones in China and Cuba that The Clown Prince so admires.  

As to 2019, it will be competitive.  If the Liberals continue to mismanage everything and Justin continues to make an embarrassing fool of himself, they could become one of only three federal governments who won a first term majority and were turfed out in their next election.

MacDonald lost in 1872 because of the railway scandal and Bennett lost in 1935 because of The Great Recession.  PET came within 2 seats of losing in 1972 but was rescued by Quebec.

However, we live in hope.