What if the social pressure, is in part, a result of the better experience one gets with iMessage?
Photos, videos, group messaging are all a significantly better experience with iMessage in my experience. This is not to say that other apps don't offer a similar experience, you can achieve much of the same functionality on Telegram or WhatsApp. It's just that it's built into the phone.
Google might have achieved similar success with their own messaging platform had they'd not constantly thrown it under the bus and created a new one every month. Allo, Duo, Meet, Google+, Google Chat etc....
Mobile messaging should be either be interoperable or cross platform. And any messaging platform that is tied to one mobile operating system is user hostile.
I received my first piece of spam on iMessage last week (used it since 2011) and it was deleted instantly by Apple. I presume because they identified and removed the account's iMessage privileges.
Any messaging app that permits spam is user hostile. Spam takes up more of my time than I would ever want to give on Whatsapp/Messenger/Text. iMessage has prevented me from contacting precisely zero people. If I were to walk away from my iPhone I would lose nothing after exporting some messages.
The barrier to entry to other potential users of $100s is well worth it for me.
Photos, videos, group messaging are all a significantly better experience with iMessage in my experience. This is not to say that other apps don't offer a similar experience, you can achieve much of the same functionality on Telegram or WhatsApp. It's just that it's built into the phone.
Google might have achieved similar success with their own messaging platform had they'd not constantly thrown it under the bus and created a new one every month. Allo, Duo, Meet, Google+, Google Chat etc....