Most of the tallest ones are now out of the ground, and there are many more large ones (700's-900's) not shown in the renders.
Honestly, the city that I can't believe is still building so much (with so much more in the pipeline) is Toronto. Why so much demand?! The skyline went from comparable to Boston in the early 2000's (less 500' towers for a very long time, although more height at the top) to now challenging Chicago. I went there once and I just don't see the draw. Ugly, soulless city.
Philadelphia is the skyline that Boston should aspire to. Ever since 1 Liberty broke the Gentlemen's agreement, Philly has not shied away from height. It has a 730' topping out now, and a new tallest (Comcast #2, over 1100' with spire) that is most of the way up!
In terms of cities getting new tallest buildings that are surpassing the Hancock, Calgary's just topped out, Edmonton's(!!!) is around ground level, and Miami has an ugly condo that is climbing.
So US cities that have gone taller than Boston now include:
NYC
Chicago
LA
San Francisco
Houston
Dallas
Atlanta
Seattle
Philadelphia
Pittsburgh
Charlotte
Cleveland
Oklahoma City
Indianapolis
Minneapolis
with a 16th, Miami, soon to join them.
Canada includes Toronto, now Calgary, and soon Edmonton.
With all the new towers we have coming, we are really just 1 new tallest away from breaking into the big-time. Hopefully we get it done next cycle.