it's a well-studied economic fact that monopolists generally sell higher quality products, and it helps them maintain their monopoly. With their market power and the fat margins they earn, there is plenty of budget to do R&D and have achieve scale benefits. Their optimum-profit product-mix and pricepoints are skewed higher. Nobody complained about IBM mainframe quality, nor Bell Telephone quality.
So, it's not testimony to Apple's prowess, it's simply a cookbook outgrowth of their product differentiation strategy.