Most of Convergint's acquisitions have been of successful or well-regarded integrators. Their claims have been that these acquisitions represent areas for strategic growth, not just buying a business to add it to the portfolio in general. Convergint also brings some back-end operations that help(ed) these acquisitions scale.
Chubb has never been viewed as the kind of company that Convergint would want to buy, at least in my opinion. They would also come with a lot of the back-end overhead that Convergint already has, creating operational deficiencies in that regard.
Convergint also likes to talk about how they keep the management teams and staff in place, and tend to grow the number of employees at a location they acquire. That would seem less likely with a Chubb acquisition, at least for the back end employees.
Maybe if Chubb was willing to sell off specific locations they might have a buyer in Convergint, but I don't see Convergint having much interest in buying Chubb as a whole.