If I was an Apple shareholder (I guess I am, indirectly through Berkshire), this would piss me off. Apple is in a very good business. Cars are a terrible business. Just compare Apple’s margins to any car company. Also, it’s really hard to move into a business that is widely outside your core competency. It can be done, but the effort is huge, and I suspect the median track record is poor.
1. Big enough market for an investment of 10s of billions
2. Its international (quit a bit of that money is stuck overseas)
3. Making electric cars isn't too hard (see Tesla)
4. Its a consumer product and they have the best consumer brand which they can easily leverage.
5. The car market is poised to be radically disrupted in the short term - electric cars/self driving cars