Bingo.
A nice house in the Philly area is roughly a $250k mortgage (depends on the down payment and other factors of course). Lets just take a $300k house with a $50k downpayment as an example, leaving a $250k mortgage. At 4.75% interest rates that we have now, that mortgage will cost Evident $1304/month + insurance + taxes.
What happens if that house drops 10% in price in the next year so that Evident can get a $220k mortgage ($300*.9 - $50k downpayment)? Well, if the interest rates rise, like they probably will, Evident is probably worse off. If interest rates rise to your 6.5% example, he'd have to pay $1391/month + insurance + taxes for the cheaper house!
Today's known fantastic interest rate is often a better deal than a POSSIBLE 10% price drop in the future.
Of course, we shouldn't look solely at the monthly payment, as the length of time he stays in the house will also impact the decision. But, monthly payments are a very important factor.
That sounds peachy and all, but the possibility of getting upside down on home value is still quite real, for a lot of reasons. Once that happens, you're basically in lockdown. For some people, it's not a problem, but it's important to realize that it limits your mobility.
Lose your job, the local economy goes to hell and you have opportunities elsewhere? You're screwed.
Offered a promotion, but you have to move cross country? Sorry, Charlie.
Your income went up and you can afford payments on a nicer house? Just as soon as you can come up with the cash to get out from under your current house, you can move...
Need cash for medical bills or a terrific business opportunity? No cashout refi for you, because you're underwater...
Lots of other very negative scenarios wrt being upside down, so, uhh, yeh- low rates aren't a substitute for the right price... Thinking that is how much of the country got chumped, and chumped us all into the current mess...