It could be that the lack of maintenance is the issue. When I take my car to the dealer for an oil change it goes on a lift and gets looked over by a mechanic (I get a video of this, so this is how I know). Tesla it not a magic carpet, it has the same suspension, brakes, tires etc. as a normal car. How often a regular Tesla gets lifted and its undercarriage is looked over? Perhaps not as often as every 10K miles when an oil change happens on my car?

And a Lithium 12V battery is not more reliable than a regular acid-lead. You can get an aftermarket one for any ICE car and some come with it as standard. It's only good in a warm climate though because in cold weather it will lose charge quickly unlike an acid-lead.