Because that's the actual maintainance cost of a car. Modulo nobody's engines need replacing in 10 years. Oil changes are 30 bucks once a year at a Walmart/jiffy lube.
The post that kicked this particular thread off even said as much but everyone seems more interested in arguing about the possible cost of the worst case than considering the actual costs of the probable cases: all the little shit.
But that alone doesn't tell me much. There's a pretty wide gulf between a gas motor that needs regular preventive lubricant changes every few thousand miles and other parts, e.g. wheel bearings, that are sealed and lubricated for the life of the part and can be expected to last a couple hundred thousand miles.
"Electric motors need oil changes too" implies something closer to the former than the latter.
In addition to the motor, the schematic diagrams above seems to many moving parts that typically need work by 120,000 miles. Eg: steering (likely) differentials (likely) and in various parts of the suspension (internal). Whilst the specifics may be debatable, most of these items are wear items and require fluid changes and/or replacement internals. Things also like wheel bearings will need some preventive maintenance. If this spreadsheet was for a 50,000 mile interval or a lease perhaps you'd overlook these. A chassis for $30K+ with 120k on the clock would bring customers looking at the cost of these services, I would venture. One way luxury brands (at least in the past have) maintained the price premium of their new vehicles is to make the 100K and up maintence quite expensive.