The point is that they have much fewer of them, not that they have none.
Not having to withstand thousands of explosions per minute (whatever RPM the engine is turning at, times the number of pistons in the engine) as a requirement is an extreme advantage.
Modern combustion engines are very robust and usually not any significant source of failure. Cars on the verge of being scrapped have everything else wrong — rust, suspension, ac lines, electronics, locks, windows, lights, etc etc.
Engine failure is a non-event. Since efficiency and emissions standards raised the bar on engine design and tolerances, even the cheapest engine is reliable.
Hell, I bought a lawn mower that had a 5 year warranty that the mower would start on the first pull.
I had a 2006 Cadillac CTS that had to get the engine rebuilt (btw, very comfortable cars, but they're basically garbage made out of styrofoam). I know it's infrequent, but it happens.
And either way, the issue isn't just with the engine-- having an ICE means you need to make a bunch of design choices you wouldn't otherwise have made, you're forced to use certain materials over others, you're forced to account for all sorts of material stress and vibrations, your centre of mass is quite high, you have a lot of weight on the front tires, etc etc. All of these other problems more or less come with the engine.
There's also transmission and gearbox design, etc.
Mine was first or second, so they kind of padded themselves in the marketing. The only time I've had it take more than 1 or 2 was when I needed to clean the fuel line. After that, right back to 1 or 2. It's now 8 years old
It's not a 1:1. ICE has things like: belts (less so now), exhaust, cooling that goes all over the place, vibration, fuel handling (injectors, lines, pump, sometimes more than one pump!), air handling with intakes and filters, sensors for all that junk (oxygen, MAF), oil and oil routing if there's a cooler, transmission cooler in some cases. Lots of these subsystems are total deletions in electric cars.
I'm not saying mechanics will go obsolete, but you're not going to see nearly as many of them. There's simply less to go wrong. I'm sure that something that goes wrong will be on the order of 10k~ :D.
I don't have it at hand, but there was a picture of the frame containing non-drive train components for the Model S, and it was maybe 2ft by 2ft.
You haven’t had to service it, except for the things where you had to service it? ICE cars also don’t need much servicing in their first five years, except for a couple of oil changes.
Not having to withstand thousands of explosions per minute (whatever RPM the engine is turning at, times the number of pistons in the engine) as a requirement is an extreme advantage.