Apple and Simplicity

Hi all, I have two questions I'd like to ask: 1) why apple has 4 different eStores and not only one integrated like amazon for example? 2) why are there three applications in Mac OS X doing almost the same (functionality) instead of one (safari - internet apps, files, services; finder - local apps, files, services and spotlight - something in between)? Doesn't this brake a rule for simplicity?