Why spend resources focusing on the Desktop, when Mobile dwarfs it in size by orders of magnitude? Mac had around 7 billion in revenue last quarter report (http

Why spend resources focusing on the Desktop, when Mobile dwarfs it in size by orders of magnitude? Mac had around 7 billion in revenue last quarter report (http://images.apple.com/pr/pdf/q4fy15datasum.pdf http://images.apple.com/pr/pdf/q4fy15datasum.pdf) but Mobile had 36 billon. 5x more. Would it matter that much if you spend a bunch of resources to increase that 7 billion to 7.5 or 8? Are those resources better spent making the next 30 billion, or even just further servicing that 30 billion? No matter how much money you have, resources are always finite and must be spent accordingly. Even if its just mental resources. May as well apply the same logic to Nvidia & AMD on Discrete GPU chipsets. Are the 30 million desktop discrete GPUs worth chasing compared to the 300 million mobile ones? Desktops seem to further increase their reliance on onboard GPUs as they service the majority of desktop needs well enough. Seems like everyone is chasing Mobile. I don't see Apple as any different viewed in this light.