That is one interpretation. However, given Android and Apple's proven ability to execute, I suspect this feature was never productized because it's not mainstr

That is one interpretation. However, given Android and Apple's proven ability to execute, I suspect this feature was never productized because it's not mainstream enough to matter. They looked at it, and shelved it. Even BlackBerry didn't do it, and their new phone is chock full of cool stuff. Personally, I think even "non mainstream" is too generous; it's a Hail Mary feature. That said, if Canonical can subsist on a fraction of 1.74% Linux market share (as measured by browser usage), perhaps they can subsist on a fraction of that in the mobile phone market, too.