I got the opposite. While you have to put parts and work into it, it never reached a “tipping point” where it got substantially different per mile. OK, axles at half a million. Engine mounts. A seat.
They were all one time deals, and his list of repairs, for which he kept a spreadsheet, wasn’t that big.
There is scheduled maintenance: oil, filters, brakes, tires. This doesn’t change over the long life of the car. It’s known, and can be planned for.
There is unscheduled maintenance. This is the surprise. The variable cost. But his weren’t that big.