If I want to "interoperate" with friends and family who use Android, I have zero issues doing so. SMS works fine, and the default experience being "bad" is really completely unrelated to any sort of antitrust concern. If we want more features, they're an App download away.
Apple offers a product that has seen significant success in a small number of markets versus android, including the US. Dressing up what is ultimately the normal bump and tumble of competition in a market as antitrust because they're winning enough in the market(s) you care about is silly.
The relevant example here is that Apple supports the lowest common denominator standard: SMS. iMessage is what makes the experience "magical" on iPhones.
The total failure of any open messaging standard to capture the market seems to imply to me that control is actually pretty important to the experience of using the service!
This is a silly argument: Microsoft's bundling of IE resulted in real damage to another company (Netscape) that had a viable and independent competitor product. Beeper doesn't have an independent product: they have a hacky workaround that Apple fixed.
What Microsoft did with IE isn't really analogous to Apple refusing to let another company free ride on their infrastructure. This isn't even as egregious as patching iTunes to break the Palm Pre sync was, and the legality of that action seems pretty settled by now.
Apple offers a product that has seen significant success in a small number of markets versus android, including the US. Dressing up what is ultimately the normal bump and tumble of competition in a market as antitrust because they're winning enough in the market(s) you care about is silly.