Future mortgage rates

[David S.]

I'm curious what the thoughts are on future mortgage rates, say 5-10 years out. 

It would seem to me that most subscribe to the philosophy that rates will stay low indefinitely, in part because that's the new precedent, but also because the Fed has to keep them low to keep payments manageable on our national debt. Traditionally I've subscribed to this view myself, but I've started to question this thinking:

Fed rates are a major aspect of mortgage rates. So long the economy and deficit are deemed stable by the market, Fed policy seems to be the number one factor that influences mortgage rates. 

But what happens when debts start to spiral out of control (as they will)? At a certain point, the market will perceive increased risk in the bond market (already happening), and the way our national debt is going this will eventually happen with US treasuries too. I'm starting to suspect that longer term, market forces will start to prevail over Fed policy, pushing up bond yields -and thus mortgage- rates, as investors rightfully seek higher yields as debt ratios keep climbing. 

I think most in this nation have fallen asleep at the wheel assuming that treasuries really are 100% guaranteed. And sure, if you can print money to pay them off, you'll get paid, but what will those dollars be worth when they have to flood the monetary supply (M2) to make investors whole? In other words, we can't just keep raising the debt ceiling forever without treasury investors eventually taking it on the chin, but as of yet this is the plan for the future. When this happens, rates will go up regardless of Fed policy. Seems to me it's another housing crisis waiting to happen, though not for another 10-20 years.

Am I missing something? Would love constructive feedback on this. The notion that low rates will prevail long term seems based on the view that market forces can be overcome by Fed policy alone, which they can't, at least not naturally.