We've lived in Oregon nearly 15 years and the only Portland area breweries I can think of that have gone under during that time are Roots, Yamhill Brewing (was in the current Green Dragon space), and Saxer/Nor'Wester (in Lake O). There have been moves (such as Mt. Tabor Brewing and, more recently, Amnesia Brewing going north to Washington), but I won't count those. I'm sure there are others that I'm either forgetting or that predate our move here in 1999...but suffice to say, Portland's been supportive of the breweries that have opened in the last decade+ (and the older ones, too)!
A couple in Sandy, Oregon have went out of business, recently Pale Horse in Salem. In Portland also there was...North End I think it was called? a very brief run a couple years ago.
Yeah, that's it... and one glorious beer review! http://beeradvocate.com/beer/profile/22916/58668/ Google Maps Streetview still shows it (closed it appears); fun fact: this space is now the Green Zebra Grocery (which has a nice selection of craft beer in the coolers and growler fills).
Portland breweries have definitely been lucky. Some with bad beer even continue to carve out niches for themselves. The other closures I remember are: Multnomah Brewing Old World Brewing in Hollywood closed, became Similarly, Columbia Gorge Brewing in Gresham closed, location became Port Halling Brewing, which closed, which became Main Street Brewing, which moved down the street and became 4th Street Brewing Liberator Brewing (and Victory Homebrew Supply) on far out Sandy Blvd. moved to old town Troutdale and subsequently closed Peak Northwest Brewing in Milwaukie Star Brewing (which included this abomination: http://www.beerlabels.com/labels/labels.pl/2400/pineapple-ale.html Tucks Brewing/The Cider Mill/Fryer Tuck's Chicken- I believe the brewer was Max of Max's Fanno Creek in Tigard The Old Chicago near Clackamas had a small brewery for a short period of time Clinton Street Brewing (which if I'm not mistaken was where Captured by Porches was brewed before they opened their own brewery) was basically a homebrew system The Ram in Lake Oswego closed but the one in Clackamas opened very quickly afterwards (though I don't think they brew anymore since they relocated across the parking lot) BJ's had two brewing locations- the pilot system near Lloyd Center and the larger one at Jantzen Beach. The Lloyd one closed and the Janzten Beach one no longer brews And there were a couple failure across the river in Vancouver- Belltower Brewhouse and CJ's And to clarify, Saxer was in Lake Oswego. Nor'wester was on Water Avenue just a couple blocks up from the current HotD. After Saxer shut down a few of their beers were brewed at Nor'wester; after Nor'wester closed both brands were brewed for a short period at Portland Brewing Almost all of these were between when I moved here in fall 1995 and 2000.
Portland's first post-prohibition microbrewery was apparently a miserable failure. Cartwright brewing opened in 1980, and closed at the end of '81.