I can't help but suppose that this move was as much for political reasons as financial ones. When legislation started restricting the importation of firearms into the U.S., many manufactures bought facilities in America where foreign-made parts were assembled or finished, which allowed them to bypass the ban.
I would not put it past the incoming administration to try and implement new laws, or creatively re-interpret existing laws, to require a larger percentage of the manufacturing of firearms to occur in this country to avoid importation restrictions. Both Colt and CZ have flagship models that are hammer-fired. The consolidation of production of these two companies could allow CZ to domestically produce more components for their firearms should it suddenly become required in order to access the U.S. market. The same logic would also apply to various rifle lines from both companies.
This may just be a sound business decision by both companies, but it could also be the first move in a political long-game.