The 320i clearly is not some thing BMW just "created" for the US market. They could have brought it here long ago but they did not. To say it is to compete with the CLA and A3 is a stretch.
The other thing to consider, 320i is sold all over the world except US, a lot of them were built for the European market. Now Europe is in the tank, where do you find the market for a model that could not sell there? Well bring it to a hot market that never had it.