Even if you could "time the market," that strategy would most benefit first-time buyers.
You see, people who already have a home usually need to sell it in order to come up with the down payment for their next home. Even if they don't, they would have to carry the debt and obligations on two homes at the same time. This can create financial hardship, even when you rent out the previous home. There are maintenance costs, renters don't always make their payments on time, the rent may not cover the mortgage and other costs, and sometimes the property may be vacant.
>So if you are a move-up buyer and want to purchase your next home during a depressed market, you generally have to sell your current home during that same depressed market. If you want to sell during a boom, then you also have to purchase during the same boom.
It tends to equal out.
Finally, suppose you are a first-time buyer and wait think the end of a boom is near? If you guess wrong, are you going to wait...and wait...and wait...till the next depressed market? If so, you could miss out on loads of depreciation...
...and that is assuming you guess right about your market timing. In 1996, when the home market was struggling, who would have predicted what the next seven years would bring?