All of this you have essentially no control over and are exposed to for possibly a 30 year period. At least with renting you can look for a better deal after a 12 month contract ends. I'd imagine a lot of people were lured to buy by people telling them house prices would never fall and lost big.
Then you move out and rent from someone who isn't charging above-market rates.
"Mark to mortgage" == vacancy. If you want to successfully speculate on real estate (as any homeowner does, landlord or occupant), you need to be willing to take losses over long periods of time.