1. The crowd here is very business savvy. If you aren't, that's cool, but understand that many of the terms we use here that you might not be overly familiar with. Here's the first result in google for the keyword "nesting": http://www.parentingweekly.com/pregnancy/pregnancy_informati...
2. Trends and stereotypes are important factors in marketing. Pretty much everyone on this site understands that there are exceptions to every trend and stereotype. They also understand that if you want to make money, you need to understand a trend and focus on it. If you want to focus on social aspects, go into government.
3. "which puts lie to your claim that they start nesting right out of college."
I didn't actually say that, and you can see from my follow up that it's a two step process: First you graduate and get a job, then you settle down and have a family. It's not important that this may take up to 10 years, it's important that the pattern is common enough that it can be banked upon to produce results.