This happens all the time. If a flight operates to a long haul destination then the crew stay a week until the next rotation. In fact the cost of hotel accomodation ( at block discount rates ) and crew allowances for the period is invariably less than paying to fly the crew one way home, and then another crew out to operate the next flight home. Even if that were not the case, both sets of crews would require hotac and days off at either end to satisfy the duty / rest parameters. This leaves little productive availability that might justify the cost to an airline.
As has already been suggested, crews can be slipped to another station that might allow for better utilization and where practical this often happens. The practicality is also complicated by the utilization of different aircraft types. Cabin crew may operate on two or three different types whereas flight deck crew may only operate one type or possibly two where (CCQ) type similarity exists.