Is that really true, or does it just seem that way because you're checking those SSC/SSP threads once a month and these threads ten times a day? I ask because I experience the same feeling and often have to remind myself how long it's actually been on those projects.
I mean, Chicago waited many years for Wolf Point and River Point, though 150 North Riverside was pretty sudden - that's not even touching the Spire. Pittsburgh has only had one skyscraper of size recently, and that one moved fast because a company with means was building it for itself (hence removing the "secure financing" and "find an anchor tenant" steps), and it still took 4 years from announcement to opening. According to Wikipedia, the Bow in Calgary was announced in 2006 and completed in 2012. That's not that far off of a Boston timeframe.
There's also the fact that we don't hear about these proposals in other cities until formal documents are filed, which means they're a ways into design. Around here, we're following it from the first possible second.
