Cambridge, Boston, MA are doing a great job creating tech he Cambridge Innovation Center (CIC) where I work clusters over 500 tech companies together. When my office needs outside expertise like intellectual property, graphic design or such I only have to take the elevator to talk to someone. We don't have to keep every expertise on hand but we can access them when we need and talk directly to them so they understand what we are trying to do.
What Boston forgot is where these people will live. CIC is supposed to be a place to incubate a company and there are apartment building going up nearby which restaurants and bars at the base of the buildings and there is a subway stop nearby but they are small over $5000 a month. How can someone incubating a new company afford over $5000 a month rent?
Obviously no one is expecting a family to live in a tech center. The model is you can live in a tech center when you are young and then move out before you are old and have a family. And starting companies is supposed to be only for the young. Older workers actually have a better record starting companies than younger workers. There needs to be places for a variety of both young and older people with families to live near these tech centers.
I think mid-sized lower cost cities could build these tech living/working centers at much lower cost than the hottest hubs.