car MAKERS make money by selling cars, car DEALERS make money by fixing and servicing cars. the biggest expense by far in servicing a car isn't parts from germany, but the $100/hr shop labour that is charged.
Many people are now leasing their cars, for those people, included servicing results in a "per-month" charge that they can write off on their taxes.
for everyone, once audi-included no-charge maintenance several years back, every one else, in order to be competitive, quickly followed suit, and simply buried the cost into that of the vehicle. trust me, the car maker isn't paying the dealer $100/hr for his tech's time, nor are they paying full price for any parts covered under warranty. however, the dealer gets "free income" for servicing for 4 years after the sale, so the onus is on the dealer to get these people into the service bay for their four-year after sales service, and hopefully get them to stay there after the 4 years is up.....
or better, get them to buy a new car at the 4 year point.
this is the ideal situation. in fact, the car dealer AND the maker are really trying to convince the customer to stay with that particular company, but at the same time, convince the customer that servicing that older car they now have out of warranty is so expensive, that it's just better for them to trade it in, suck up the depreciation, and purchase or lease a new car.
for most cars, as an aside, oil changes every 3000 miles is unnecessary. if you were to do an oil-analysis, most oil change intervals would be in the 7-12,000 mile range, especially with synthetic oils, which is all I ever use.