First, the article assumes each developer creates one app (160,000 * 8700 = $1.392B revenues, $1.392 * 30% = $418mil "profit"). This error leads to further errors down the line.
Second, Apple App Store sales is estimated to hit apx $4.9B 2012 [1]. This means apx $1,470mil in gross income (what the article calls "profit"). The article uses only $1.39B revenues and $418mil in gross income in its calculations as outlined in point one.
Third, this analysis assumes every developer would not purchase an iPhone if they were not developing software. Given that the vast majority of iOS developers do it part time, I think this assumption is highly unlikely.
Fourth, including profit from phones as a % of appstore profits is just wrong. Phone profits are not included as part of appstore profits. Thus it cannot be used as a % of it. It is additional income, on top of the appstore.
Finally, just to give you an idea of how little profits from developer matter... In the last 4 reported quarters, Apple earned a pre-tax net income of $49,000mil. Or $134mil per day. This versus the article's $64mil over the entire year from developers. Somehow I don't think they spend a lot of time or effort trying to get money out of developers.
[1] http://www.mediabistro.com/appnewser/apples-app-store-revenu...