Of course the difference between Google/Microsoft and Apple in 1997 is that Apple didn't have a profitable core business (Windows and Office for Microsoft, Adwords for Google). Google and Microsoft can afford to spread out, but Apple's only chance in 1997 was to focus.
It's also interesting to note that in their early days, both Microsoft and Google were very focussed. They started to spread out when they started earning more money than they could spend. Apple, on the other hand, stayed focused. There is no Apple product that doesn't have a clear purpose.