I watched Seattle build like crazy in the late 90s. It seems like every month a huge skyrise apartment building came online in Belltown. Many thousands of units were added every year. It coincided with a continuing influx of people so I don't think it lowered the absolute price of real estate, but the laws of supply and demand are pretty inviolable. Seattle is pretty affordable by present SF standards, and with much of the same cultural appeal.

(I live in SF but used to spend lots of time in Seattle)