I have never heard that 401ks caused the bubble and would love to see more than one source that says this.
Also notice that the housing crash happened just as all the baby boomers' children go off to college and they decide to down-size from their McMansions since they are empty-nesters now.
Thirdly notice how now medical expenditures nationwide are climbing greatly now that they are all becoming old and sickly. The next 10-15 years are a great time to be in the medical field, even with ObamaCare. But then as they die off it will be a horrible place to try to get a job.