Apple will be a very small part of the auto market for the first few years. They will sell a very limited set of options, at the very high end of whatever market segment they enter into. They will sell enough, but not many, units at first, to those who want the status, the prestige, and the interest of owning one of Apple's first cars. In addition, the Apple car will be able to do some things better, easier, and cooler than other cars on the market (e.g. using their proprietary battery technology and development of likely very efficient EV motors). Slowly, over the course of several years, they will diversify, offer new models, at different market segment points, foregoing the lower end of the market, to maintain large margins at fewer sales. This is what they did with the Mac, the iPhone, the iPad, the Apple Watch. Does anyone else remember "gold plated" Apple Watches that first year? Also, Apple (Tim Cook's specialty) has demonstrated that it has the capacity to develop incredibly tight manufacturing processes and supply chain and inventory logistics. This is essential to auto manufacturing success, and why Tesla has never made a profit on making cars (all of its profits are for selling carbon footprint credits to other companies). Apple will succeed, and might even be a dominant player by 2035. Remember, there are going to be massive tax incentives to move to RVs in the next few years. Infrastructure for EVs will also ramp up quickly, matching gas stations in the not-too distant future.
Apple's obligations to its shareholders almost dictates its attempt to get into the auto industry. With apple so huge in the market segments it currently dominates, real growth options are pretty limited. Cars are "the next big thing" and they will be a natural extension of its overall ecosystem, becoming an integral part of how you use technology from when you get up in the morning to when you go to sleep at night, integrated with your communications technology, home technology, etc. It is also very possible that Apple will create a new way of "selling" cars, by developing fleets that it owns and maintains, with users leasing cars as needed, thereby lowering per use cost. I am guessing auto ownership will be far less common in twenty years. Think Apple's version of an Uber that has no driver.