This disregards the fact that many iPhone customers are still first time buyers with no lock in hanging over their head. And also Apple has an extremely high customer satisfaction rate keeping customers coming back. Customers buy iPhones because they like the experience and ecosystem, not solely due to some service lock-in.
Google Hangouts seemed to be a step in this direction as well, with SMS integration, it pushes users to use their proprietary protocol instead where possible. But it looks like Google has backed off of it since then.
The author also argued that Apple's lock-in like iMessage isn't really working. Thus, this is how Android gets to 100%.
To put it another way, if everyone you know is using ACME OS, then it is highly likely you will start off by using ACME OS.
I might believe you if you said the US, but given how low iPhone penetration is outside the US, combined with how many new people use the Internet for the first time each day in India alone (100,000,000 per year, most of that being accessed over a mobile device), it's clear that smartphones haven't hit 100% potential market penetration the way "food" has.