To answer your question we need to know where you expect to be 5 and 10 years from now, proessionally, personally, and geographically. Also, why did you decide to buy such a huge house in the first place? (The answer to that question culd be illuminating). And wuld you pay near $1MM for a house that wasn’t in move-in condition?
That said, if you think that you’ll stay in the same area for the next 10 years, it may be best to stay put and work dilligently towards paying down your $600K mortgage. I know you said that all your money goes into the house. Is that really tru? For instance, how much are your car payments? If you bought a used Corolla and shared it among the two of you, and kept it for another 10 years, you could have some substantial savings. The same is true of eating out, giving to charity, travel, etc. You can find money to pay your debt.
If you work hard towards paying off your mortgage, and then you sell the house when the next boom peaks (not earlier than in the later part of the next decade IMO), you’ll have a huge nest egg to retire on.
Forget Zillow. My old house, which I sold at the top of the market in 2005, now it’s valued by Zillow at about 23% over what it could realistically sell for today.
