In the case of Tesla, their gains in reliability are directly transformed into a lesser demand for servicing. Once they get into a inflection point with their fit and finish quality they will likely become less dependent on having a traditional service infrastructure. Instead they can double down on more unorthodox models like mobile service.
Traditional manufacturers, in particular Japanese manufacturers, already achieved peak reliability in ICE vehicles. But even with that, they still need to have a service and maintenance footprint because their cars still break.
The average-reliability EV breaks way less than the top-reliability ICE, so you really need way less service infrastructure if you only sell EVs.
I think not. I have a Hyundai Ioniq, and I still have to change tires 2x a year, fill up wiper fluid, change the pollen filter, get AC/heatpump fluids checked. I had to get an axle boot repaired for 200€ - these things happen to any car. EVs (even Teslas) also have a conventional car battery for backup power - this will die every 4-5 years. People might key your car, or bump into you. If you own a „Monday“ Tesla, chances are you‘ll spend more time at a garage in the first few years than a gasoline Kia or Toyota.
Will you spend less on maintenance? Very likely. An order of magnitude less? Highly unlikely!