While "the system" is absolutely at fault for this, lifestyle creep --- and changing finances --- is very real.
For example, if you can almost afford a house, and your rental is modest, you're probably not spending all of your take-home. But if you make just a little bit more it might make financial sense to buy a house, stretching your budget to the max. Short term this really hurts, but long term may end up being a savvy decision.
Opting for a hefty mortgage can be risky, but can also pay off in the long run --- especially in a place like California where property taxes are basically fixed at time of purchase.