Earlier quoted context omitted.
That's not really what lock-in means. An example of lock-in is making a conscious decision not to port iMessage to Android, specifically because it would make it easier for iPhone users to move to Android[0]. Making Apple products work well with other Apple products isn't lock-in. Purposefully making Apple products work worse with other systems, phrased within the company as a way to punish users who switch, is the k…
>Making Apple products work well with other Apple products isn't lock-in. Cool. iMessage works perfectly well with SMS, which is the only true open messaging standard, and therefore will work with anything else that interoperates with SMS. Job done.
So iMessage app doesn't work like SMS reading app. It forces you into using iMessage account to just read an SMS. Later it lures you into using iMessage instead of SMS to make it harder to switch to another OS later.