One way to try and forecast the demand for new skyscrapers is to look at the industry mix within the City. You can find the largest employers within the city of Boston here.
http://www.bostonredevelopmentauthority.org/pdf/ResearchPublications//pdr509.pdf
Currently the health care, insurance, finance and education industries dominate Boston. Most health care and educational institutions have no need for large office towers. The hope lies with the insurance (see Prudential Tower) and finance (see Federal Reserve Tower, Exchange Place etc.) industries. Look at Charlotte, why does it have such tall towers? It is major banking center. If these industries decide to expand their operations within the City of Boston, then you could see newer, larger skyscrapers.
Another way to forecast the demand for skyscrapers is to look at population growth. A large jump in Boston?s populations could fuel new demand for downtown high rise living. This link shows population growth by metro area from 1990-2000.
http://www.censusscope.org/us/metro_rank_popl_growth.html
Boston is all the way down at 229. Another good report on Boston?s future can be found here.
http://www.massbenchmarks.org/regions/boston.htm
Residential demand has peaked in the city center do to the availability of high end jobs and services. But the region as a whole is not growing at a fast enough rate to supply the area with a large scale residential towers.
A third way of anticipating the demand for new skyscrapers is assessing the impact of local politics. It is clear that Mayor Menino has been unable to build enough consensus to push his plans for taller buildings through to completion. Furthermore the political history of Boston?s built environment is one of destruction and regret (see West End and Government Center) along with bungling and incompetence (see Big Dig). This leaves little political will for large scale improvements and it promotes a vigorous defense of the city?s historical character. This can be stifling and stultifying for new growth. Boston has never been a place for tall buildings, see the height restrictions during much of the early 20th century building boom. It is also not a place for innovate architecture. Rather it tends to favor conservative styles that blend in with the surroundings.
Finally, you have to examine the cityscape itself. Boston?s downtown core is largely built out. There is very little room for new construction. Most if not all new buildings would have to be build upon existing structures. This leads to clashes with historic preservation groups. Furthermore given the tremendous availability of historic housing and neighborhoods, residential growth has spread out horizontally rather than vertically. There are plenty of fantastic neighborhoods within the city and its suburbs to settle leading to a lessening of demand for new high rise condos.
One last point deals with Boston?s image. Is Boston a striving city, trying to define a brand for itself that it can project to others? No it is not. The City has a well established brand that connects to its historic architecture, living history and quality of life, not its skyscrapers. It simply doesn?t need tall buildings to fulfill the role of herald to the world.
Personally I?d like to see one taller structure rise out of Boston?s downtown to give the skyline a better proportion. Boston?s skyline is great for the breadth and length, from downtown to the Back Bay. But its buildings are largely subpar. Living in Chicago now I don?t feel the need to defend Boston?s skyscrapers anymore. Most lack all sense of grace and proportion. Chicago is full of gorgeous architecture that I marvel at constantly. But it built its legacy upon that fact. It is part of the cities image and aura. Boston will see tall buildings for sure. Political will might change. One hotheaded developer can build a great building. In the end I thought I?d just give my 2 cents.