Why are there no team breakaways in road racing?
While a breakaway could be organized by a team, the peloton would not allow it to succeed. The mechanics of 8 or 9 riders, even excellent riders working together, are such that the maximum sustainable speeds would not be high enough to stay away from the peloton for long enough to matter, and every other team would develop a vested interest in ensuring that the breakaway was caught. 

The GC advantage of a team that succeeded in such a maneuver would be all but impossible for other teams to recover from, so any every other team would work together to make sure it didn't succeed. 

Breakaways are often allowed by the teams in the peloton as it gives the GC teams a lever to play rivals against. Which team will have to expend the energy and manpower to reel in the break? How is that going to affect their chances tomorrow?

Edit: 

And to add... An entire team breakaway would be a waste of "specialists" energy. For example, a entire team breakaway to win a single stage, could ruin a climber's chances in a mountain stage the next day. – Courtesy of *wdypdx22*