The point is you'll never need to replace the engine in a BMW unless you got into an accident or something like that. EV batteries will just degrade with normal usage.
That's simply not true - of many makes of car, but BMW in particular. There are lots of issues with combustion engines which can be fatal - look at the issues with vanos bits dropping into them, camchain failures, etc.
I buy and sell cars as a side gig, and there are plenty of models which people like me would not touch with a barge pole because of issues like this - many of them German - and you'll find many for sale as spares or repairs, and find that secondhand engine supply is low (as many have blown up), and therefore expensive. Look at a diesel vauxhall insignia, for instance. Hand grenade engine, no chance of getting one secondhand (and even if it did, its got the pin pulled).
I'm sure there are exceptions, but engine problems are way, way less common than the accepted degradation of batteries over their lifetime. Most car engines keep working well even after running 100-200k kms. There is no "accepted" degradation into uselessness as we have for lithium batteries.
The same degradation happens with ICE engines - they lose power and become less efficient.
And batteries which are thermally managed (ie anything but an old leaf) will have a better lifetime than a typical ICE engine -tesla easily achieve 300k miles with less than 10% range loss.
