It USED to be the break-in period was super important. I've been told that it's not anymore, but that comes from salesmen. So. Who knows if it's accurate or not. I also do not know how that applies to the electric motors on a new electric vehicle.
But I'm betting that's the reason.
Will the transmission last 5000 extra kms or the engine will make it from 500,000 to 501,000 km? No one seems to know.
Makes it feel like poeple telling me I have to discharge a battery all the way because it has "memory" long after most batteries were lithium ion with a charge controller.
The reason you don't get a scientific answer is because that's just not possible.
The difference between replacing a wearable component at 100,000 km or 101,000 doesn't make a huge difference (ignoring the fact that it could just fail earlier due to one of a hundred different environmental reasons)
Anyone that has done car work knows that if you run a magnet through used oil or look closely at used grease that it will be full of tiny tiny metal shavings from this action. It is just more intense during the first hundred or so miles.
EVs should greatly reduce the need, but there are still moving parts in wheels and sometimes gears.
Stay under 90mph for the first 1300miles (lol that's 2000km), and for tires and breaks, it's good to let someone else drive for you and take the risk of not yet fully functional components.
The owner's manuals still recommend a break in period. Modern synthetic oils and manufacturing tolerances reduce the need to be sure, but there's still a whole bunch of parts built at different plants that have never really worked together before. A bit of controlled wear still makes sense to me.
Having said that, once production is in full-swing, they are unlikely to get full "burn-in" tests.
Early production may get a little more for various reasons.