Apple is a high-end electronics company, not a charity. This is as ridiculous as asking why Ferrari doesn't make a R10 000 car.
As to innovation, 75% of Apple's revenue comes from product lines that didn't exist 5 years ago. Care to name another company who can claim anything near that?
You see, while I agree with you when you looking at it from afar. But the reality is that Apple is in a very different position to companies like Ferrari, BMW, etc. Infact, its one of a very few companies to be in the position they are in. From a business profitability point of view, they're rocking. Their business model is sound, and its a cash cow. So I understand your reasoning when you say - why change anything?
Well here's the difference.
Apple, unlike most of the companies mentioned for comparisons sake, produces cutting edge hardware and software, empowering those who use their devices to have access to knowledge on the tip of their fingers. Apple is also a top innovator, with multiple awards over the years. Apple is in a position to change lives.
Apple are at the forefront (whether they like it or not - cannibalisation of their own desktops) of the downfall of the wide-spread usage of PC's. Laptops are becoming more prevelant and so too are tablets. In Africa, and in most cases, prices and customer confidence dictate the growth and adoption rates of these newer devices. Of course, education is a major player as always. We've recently seen the ultra cheap (and lean) Akash tablet being released in India. Here we had a small group of innovators creating a device to serve the less-fortunate who would never have even had access to a PC yet alone the internet.
I guess what I'm leading towards is that Apple should be innovating above and beyond what they've seemed to settle for. They're in a position to leverage off their skills to create a device to uplift those who would have never had the opportunity otherwise. And if you talk revenue, I'm sure the business case guru's could come up with a feasible and highly profitable scenario. If I'm correct, Nokia still makes truckloads of money from the sales of their lower-end (dumb) phones. So perhaps there is a commercially viable case, and perhaps not. I'm not sure, but I'm sure that award winning innovators and trend setters could figure this out...
