There's also a few reasons not too...

1. Prices have risen more rapidly then usual over the last few years an many believe we are in another housing bubble.

2. The expenses of owning a house are usually much higher than renting. In addition to the mortgage, you must also pay property taxes, insurance, and whatever costs are involved in simply maintaining your house. Rent is usually more expensive than a mortgage payment (for the equivalent house) but it's often quite a bit less than the other expenses combined.

3. Freedom kind of works both ways here. Yes, with owning a house you have more freedom to do what you want with it but if you are someone who likes to move around a lot then it is not all that practical.