Sunset
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
Well, that's the thing. You were making a decision for a long-term investment based on a short-term timeframe. That is almost always a mistake, financially.
Sure, in 2008 4% was a good return. But by paying off the mortgage you locked that money in, and now that the market has doubled from then -- you missed out on all that.
Back of envelope figures:
Say you took out $100K from the S&P500 in 2009 to pay off your $100K mortgage. That saved you 4% * 7 yrs = 28% = $28,000.
If you had left in in the S&P500, it would now be around $200,000. Minus $28,000 of mortgage interest = $172,000.
You could now pay off the $100K mortgage and still have $72,000 remaining.
That short-term decision cost you $72,000 long term.
Everybody is different, but me -- I treasure having more money more than I treasure having no mortgage.
You are cherry picking the dates in your example instead use Aug 1, 2008 since they paid it off in 2008 (not 2009) and they get a 70% increase.
Which would be 170K minus the 28K mortgage interest = 142K
So not quite as good.
While in general , what you say is true very often, sometimes it is not, take the case of 1929 when being in stocks was a killer.
I'm one without a mortgage, and although these low rates are tempting to lock in a large borrowed amount at low rates, I counter that with the fact that being mortgage free is a hedge against something that would make stocks or other investments worth much less.
Could even be as simple as 90% tax on any earnings.