While it's definitely a terrible idea to fossilize a city, some parts of town are entirely unrecognizable, even from what they looked like three years ago. I don't long for the SLU of old or the abandoned lots of the Denny triangle, but there was an entire "sense of place" that was wiped out almost overnight. The wrong people are blamed for it, but I can completely understand where the grievances originate.
I'd place the blame most squarely on the NIMBY establishment and our single family zoning. There were bound to be growing pains from all this growth, but they didn't have to be so extreme. If we could upzone Magnolia and Wallingford, it would give the CD/south seattle renters quite a bit of relief.
I also think that the HQ2 stuff has much more to do with hitting the limits of our transit and housing infrastructure than the leftward swing of city politics, but that's probably best left to another post.