I think the question is how practical third-party service will be (by individuals or independent garages). As you suggest, the common wisdom that I've always heard is that, if you want to hold onto a luxury car past the warranty/extended warranty timeframe, that's great and can be a fun and cost-effective auto--but only if you're handy and willing to spend the time or have an indie mechanic who you trust. Otherwise, dealer service will eat you alive.