Apple spends remarkably little on research and development, less, in fact, than any of its peers. Last year, according to its annual report, it spent only two and a half billion dollars. Over the past five years, it has spent, on average, less than three per cent of its revenue on R.&D. Microsoft has spent fourteen per cent, Google thirteen, and Amazon five and a half.
Apple does a few things very well, and they tend to put all their R.&D. money into these few things (phones, tablets, laptops, operating systems, maybe televisions) and stuff that makes those products work better (faster processors, better batteries, and, as of recently, cooler fans).
For comparison, Nokia has as many people working on R&D for smartphone software as Apple does for all its products.