I think that this article is basically right, but would add that bubbles are generally dangerous based on what they represent, financially and culturally. If Bitcoin hits $1,000 again, it's not innately dangerous (unlike housing, no one needs Bitcoins to live). It might represent a bad thing, like the collapse of a currency.

We're still in a housing bubble (although not as much as one, and one with a sharper geographic profile) but what's propping it up now is industrial decline and extremely lopsided job availability. Much of the country is starved of economic activity while a few metropolitan areas (e.g. New York and the Bay Area) have healthy job markets but extreme real estate costs.

All of that said, I have no way of predicting how that bubble will resolve or when it will crash. We could see it happen in 2 years or in 25, and it will probably vary with geography (just as Vegas and Florida got hit hard in the last one, but the Bay Area and Manhattan remained unscathed). Housing bubbles are weird because there's so much corruption (foreign money, NIMBY regulations) involved that makes them political and therefore unpredictable.

The 2001 tech crash didn't do a lot of damage to the rest of the world (9/11 did far more). The 2008 crash is still being felt in Southern Europe. I can't predict how much of an effect the ~2017 VC-land crash will have. To be honest, the numbers don't look that bad; when Silicon Valley drops a turd like ZNGA on Wall Street, the Street usually reacts with proper skepticism. So I think that this one's going to be relatively limited in terms of its impact on the rest of the world. I don't like what it represents about our society, and what it may continue to represent, because that is corrosive. The truth about VC-funded startups in the Bay Area is that 98% of that stuff has nothing to do with creating new value, but with devising ways to profit from widespread organizational decline.