Right now, sure but doesn't seem to be their strategy long term. Why would they purposefully sabotage that as you're suggesting?
I consider any manufacturer that isn't making moves in that direction to be demonstrating an unserious attitude toward EVs. CCS is a total shambles in the United States and its headwind should cast doubt on any advertised optimism from manufacturers using CCS.
In this case while I prefer NACS myself, I'm worried that convincing a dozen manufacturers to switch standards is going to take much longer than just adding a second CCS connector to (many) Superchargers. Otherwise we could lose years to this, and still wind up with CCS everywhere.