There’s a political challenge with house prices. They are too high for would-be first-time buyers to buy—average house prices are affordable only with the highest 15 or 20 per cent of incomes. So would-be buyers need lower prices. But the 65 per cent of Canadians who already own a home tend not to want prices of their homes to fall, even though those homes are now worth several times what they originally paid for them. About 75 per cent of homes sold each year are existing homes. You can’t prevent those prices from falling and have lower prices for would-be buyers.
For that reason, new federal housing minister Gregor Robertson got a lot of flak for saying he didn’t think current home prices need to come down. What he—and Prime Minister Mark Carney—have argued is that by taking the GST off new homes for first-time buyers and cutting development fees in half, plus helping the home-building industry become more efficient, prices 
for new homes will be lower “than they otherwise would be,” as Carney put it in a recent interview. However, Carney added, even if GST and development fee savings are passed on to buyers, “that amount of activity isn’t enough necessarily to affect the overall level of house prices.” The core issue, he said, is that “the level of house prices goes down relative to their income, so the affordability goes up for them.” Watch Carney’s answer here, starting at about 20:30. (None of this discussion touched on what proposals the new government may have for the third of Canadians who rent.)
So, if housing prices stay stable—that is, they don’t fall but they also don’t rise—how long would it take for incomes to rise enough to make those home prices to be affordable? Housing researcher Mike Moffat did some calculations and the answer he came up with is, at least two decades in many Canadian cities to be as affordable as they were 20 years ago. The time required varied for different markets and with different assumptions about how fast incomes might rise, how high interest rates might be and how much people might be able to save. You can see his calculations here.
In short, the proposed federal measures might lower new house prices, which might lead to lower resale house prices, but realistically, you can’t get affordable house prices without lowering prices.