That likely plays a part, but I think that the network was in the past something that Tesla had to build in order to make the mission work.
Time has passed. EVs have achieved the tipping point threshold, and now that charging is becoming more crucial (and lucrative) others will finally be stepping in. Elon realizes Tesla can throttle back on that front. This frees up resources for focus on aspects of the mission that are more necessary for Tesla to focus upon, as you indicated.
The Superchargers are another example of where Tesla led by making a reliable, world-wide network to prove it could be done. Now that the model is there to copy, Elon knows that over time, only reliable charging networks will survive and letting them make mistakes and grow with less competition from the example they must emulate is good for the mission.
Now, local interests can decide where and how they want to have their chargers. They can come to Tesla and purchase them, along with a service contract. Or, they might go to another supplier. Either way the available charging options will continue to grow in pace with EV adoption.
Tesla getting out of the business of micro-managing site selection, permitting, and all the other burdensome local work that cannot be efficiently accomplished from a remote location, is a smart move.
Tesla can now steer feedback from user requests for new locations to those companies approaching Tesla about buying and installing chargers for fun and profit. Tesla has the knowledge and expertise to help them get that job done, without having to commit employees to managing the harder local tasks as had done before.