No. Two weeks. As was fairly widely reported, this was a very sudden decision by AA. They literally stopped using dnata, in the interim catered all ex-LHR flights from the US, and had switched to Do&Co ex-LHR within about 2 weeks of the initial decision to can dnata.

So it can absolutely be done. It just requires serious motivation. Which UA has totally lacked ever since it unwound the original Polaris meal improvements.