As the saying goes, Velveteen, all I know is that everything you know is wrong. Allow me to correct your premises in a pointlessly dickish manner. (You're welcome.)
For starters, apartments aren't going up "all over North Portland." They're going up all over Portland, period. According to Multifamily NW (like a fraternity for landlords, except they do keg stands with money instead of beer), there are some 22,000 new units in the construction pipeline.
As to the market imploding, we should be so lucky. As you may recall through the bong-filled haze of Econ 101, a collapse in demand would result in falling prices for renters like you (and, more importantly, me).
There appears to be approximately zero chance of that happening. I have before me Multifamily's most recent report on the Portland rental market, and its digital pages are practically stuck together with excitement over all the money to be made off of chumps like us.
Our current citywide rental vacancy rate is just 3.1 percent, and it's close to 2 percent in some neighborhoods. (A "normal" rate is around 5 percent.) This supply-and-demand mismatch may make renters feel like the invisible hand of the market is giving them the finger, but it's sweet, sweet music to the rentier class.
In fairness to our capitalist overlords, the current spate of apartment-building should mitigate this shortage enough to keep rents from rising as fast as they might otherwise.
Of course, where all these new residents are going to put their cars is another matter, and the dust is far from settled on that issue. Parking is the new fluoride; you heard it here first!
QUESTIONS? Send them to firstname.lastname@example.org