It really doesn't matter what the percentages are. At some point, the growth rate for tablets will start to slow down. By then, if you aren't already working on the next big thing, you're in trouble.Don't apply the phone dynamic to Tablets. Android is not likely to take a lead in tablet market share for a long time if forever.
The point is that Apple is likely to be working to be working on that product already. The question is whether companies like Moto, Samsung, and HP are.