Anecdotally: suspension and steering components wear a lot more than drivetrain components under northeastern US driving conditions. And electric cars will have springs, struts, dampers, sway bar links, tie rods, ball joints, and all the rest of the parts that are routinely exposed to dirt, salt, and water and subjected to all manner of forces from random angles.

By contrast, under normal operating conditions, most of the wear parts of the engine and driveline are running in a sealed environment, bathed in the appropriate lubricant, and, in the case of the engine, actively cooled to maintain optional running conditions.

Al the parts that make up an ICE are incredibly mature technology. The engineering work to get the tolerances and everything else worked out that has been done over the last hundred years is unreal. And it's happened in concert with work by chemists in the lubrication industry, and every other ancillary industry. The level of reliability under normal use with regular maintenance defies belief. Like, when was the last time you gave your spark plugs even a moment's thought? The progress in metallurgy, fueling and ignition systems has made them an all but lifetime part on modern cars.

I would actually wager that for most people, the least reliable and most aggravating part of their car is now the infotainment system.

least reliable is the battery. In texas, 60 month batteries only last 3 years. One day you try to start your car and it simply wont start. Thus requiring a jump start. I know what to do here, but many people I know have to get their car towed.

I carry a portable jumpstarter because you just dont know when your car will refuse to turn on.

12V batteries have entirely different chemistry and (no) management compared to the high-capacity 400V batteries.

At this point long-term real-world data is available for Tesla Model S, and it loses about 4-5% per 100,000 miles.

Of course the 12V starter battery has a BMS. At least my car has it (Ford Focus 2017)