There’s more to it than software updates.
EVs in general, I can see having issues. Many of the manufacturers are still on their first-generation EVs, and they're just not very good at them yet. Companies like Tesla and GM that have been doing EVs for a while should, IMO, be more reliable. However, that particular study goes back to the 2000 model year, so it's covering everybody's first-generation EVs. I don't think it's particularly relevant to look at an EV1 to decide whether a brand new Silverado EV is going to be any good. Same with a Tesla Roadster vs a Model Y.
If they were maint free, you wouldn’t have so many complaints about service centers. 1.7 star average. Somehow they have high customer satisfaction though.
Nobody likes going to the service center, regardless of what kind of car it is. It's annoying, kinda wrecks your day, and costs a lot of money.
In nearly 70,000 miles, I've had my Tesla into the service center four times, and two of those were due to FOD encounters (screw in a tire, and two bad windshield stone hits in quick succession). I've knocked a couple of plastic pieces loose and had them refitted.
In terms of maintenance not caused by outside forces, I've had the tires rotated, and I've had the cabin air filter replaced and ducts cleaned out a couple times (HVAC system design can cause a lot of condensation that causes smelly things to grow, it now operates differently thanks to a software update and no longer has this issue).
And I've put washer fluid in it.
Somehow, the factory wiper blades are still good. Brakes will last forever, and I use the actual brakes just often enough to keep the rotors from rusting. I'm about due for a new set of tires.
It's amazing how little needs to be done when there's so few moving parts, so much less vibration, etc...