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!

That doesn't seem like a comparable scenario; Apple implements the Bluetooth standard (along with a bunch of others), which is defined by industry groups.

In this case, it's not a standard.