That's what I was getting at. Mobiles with stem walls are almost always "Permanently Affixed" to the property when set, for tax purposes through the county assessor, and the mortgage company that is handling the sale.
MH's have transitioned over to sheetrock, tape and texture in the last 25 years, no more "tacky" paneling, and tearing them down for transport and the transport itself can cause a lot of damage to the interior walls.
And you're right, it IS pretty expensive to move them (removal and storing of your household items, teardown, tongue/axle rental, transport, DOT permit, escort vehicles, placement permit, ad valorem tax check and transfer, leveling, marriage line attachment floor, walls and ceiling, new roof cap, utility hookups, etc....) For the cost and PITA, you might as well upgrade to a new unit and have it set in your new location.