Some good analysis there, though I've often felt the smartphone / tablet split is false and at least in Android will blur over time to become a moot distinction (as soon as telcos stop being useless, so this may take some time). We already have a word for it: the phablet. If lots of people buy Galaxy Notes and Xperia Z's instead of slightly larger Nexus 7s does that mean Android has failed as a tablet OS? I know I originally bought a Note rather than have a tablet plus phone.
When Apple only had 3.5" phones and 10" tablets there was some possibility of taking the moral high ground on this one and claiming anything smaller wasn't a real tablet. It's a lot harder to argue that with an iPad mini on the market.