Ah, but probably a single repair on that BMW will be more expensive than 5 years of repairs on my Corolla.

It depends on the country. BMW are well known by any mechanic and parts are widely available, OEM and aftermarket. In my experience BMWs are not more expensive to repair than any Toyota or VW, but due to the increased set of features they have a higher failure surface.

Only if you do your repairs at the dealership

As a BMW owner, I actually found the repair pricing quite comparable. Maybe not quite to a Corolla, but it was to a Lexus.

If anything the Lexus was a bit more, due to how common BMW specialist shops are, while there's none for Lexus.

The issue for me was the frequency of the repairs, 5 years of Lexus ownership cost me less than any 3-4 month period of BMW ownership over the 2 years I owned it.

I suppose I can only compare 2-3 repairs, cause the other dozen repairs for the BMW simply didn't break on the Lexus, nor did it spring any of oil leaks my BMW was famed for.

Your mistake was taking it to a Lexus dealer. The cars are nearly identical to their Toyota counterparts so most mechanics can work on them