There are plenty of less obvious synergies if SpaceX and Tesla were one company.

Data is one. Between them, they have access to many kinds of data Tesla vehicles generate mobility, road, and environment data like starlink provides connectivity and network-performance data and space X  has aerospace telemetry and operation data

Their factories generate robotics and manufacturing data , this can improve AI systems for autonomy, logistics, network optimisation, and robotics

Together, they can secure better supplier terms, priority access, and deeper supplier relationships.

Talent. They can attract an elite engineering pool, and culture and talent can move across the system, between rockets, AI, robots, and energy.

And imagine a disaster area where roads, power, and communications are all down. This combined entity could offer complete disaster relief:

Starlink for internetwhere as Tesla Megapacks for power vehicles for transport And also robots for dangerous cleanup, Ai for coordination and triage

finally it is almost scary how powerful and vertically integrated Musk’s companies have become. One does have to ask: is it healthy to have so much power and wealth concentrated in one man?