It’s one thing to rely on someone for manufacturing than to rely on someone for research/design/patents and manufacturing. In theory once Apple gets this project up and going they can have multiple manufacturers (if they want) and they would always have the option to manufacturer in house in the future.
It’s like their CPUs and TMSC versus using a Qualcomm Snapdragon. Sure, TMSC is manufacturing Apple Silicon, but Apple always has the option to port their design to a competitors node process or even spin up their own fab if needed (highly unlikely but possible).
