It's obviously a smaller market. I'm just suggesting that it's possible, and providing some anecdata.
From a real standard of living, the cut in pay is overwhelming made up by the fact that I live in my own detached 2k+ sqft house on a .25 acre of land (and at significantly less than $3500/mo). Again, just looking at the city of SF directly, there are 13 homes for sale under $750k with a min of 2bd/1.25ba. Take a pay cut, have access to 40 times as many houses.
It's possible to do software development and not pay $3500. Which was what the above poster was talking about "I'd love to stop paying $3500/month in rent, but any property to buy around here has a median price of $1.2 million."
the most important differentiation between Portland and SF?
Also, the most important differentiation between Portland and SF is the weather. Anyone will skill can get a job here (I've never had to look more than a couple weeks).