This is changing soon. SpaceX filed with the FCC for approval for mobile ground stations on vehicles like RVs, boats, and planes. It's coming! https://fcc.report/IBFS/SES-LIC-INTR2021-00934/3877177.pdf
I’m guessing roaming clients is how they are actually going to make money.
It sounds like they don't support a roaming base station for now. From the FAQ: https://www.starlink.com/faq
Can I travel with Starlink, or move it to a different address?
Starlink satellites are scheduled to send internet down to all users within a designated area on the ground. This designated area is referred to as a cell.
Your Starlink is assigned to a single cell. If you move your Starlink outside of its assigned cell, a satellite will not be scheduled to serve your Starlink and you will not receive internet. This is constrained by geometry and is not arbitrary geofencing.
Sounds like some sort of authorization comes down from the satellite, and they don't want to have to push all authorizations from all satellites. Which is odd for a full duplex service. Searching around google suggests a "cell" is roughly a 4.5 mile radius circle, and you probably aren't in the center. So movement would be pretty restricted.