You can explore the scenarios in which it is better to rent or to buy using this application:
http://demonstrations.wolfram.com/BuyOrRentInvestmentReturnCalculator/
In the possibly unlikely scenario shown below, at the term of the mortgage (20 years) the tenant and the buyer have practically the same return on investment. At this point the tenant's savings would be sufficient to buy a house equivalent to the buyer's, and this would be the advisable course of action (based on the figures alone).