Really? Do you what makes Apple shareholders happy? It starts with happy Apple customers who love to purchase Apple products year after year after year, causing huge product sales volumes and company revenue.
Apple has 2+ Billion active and repeat customers causing the above to occur. As just one example, Apple manufactures and sells roughly 600,000 iPhones per day, every day of the year (on the average). Helping to make Apple one of the most successful tech companies in the world.
Thus for the above to occur, it's paramount that Apple create products its customers love to repeatedly purchase. If that were not the case, there would be very little Apple sales and revenue. Which would cause Apple stock to tank, and make Apple shareholders very unhappy, causing them to no longer invest in Apple.
In simpler terms: Apple creates outstanding products their customers love ---> Outstanding Apple revenue ---> Apple shareholder happiness.