Sounds like it would be easier to find new friends.
Seriously though, iMessage should have some sort of interoperability on other devices, even if its just a web interface you can log into to make configuration changes, including the deletion/deactivation of an account associated with a mobile phone number.
Edit: Or even monitoring iPhones associated with a number and disabling iMessage if said phone is no longer online with that number? Could possibly even forward unread messages, etc.
Though this only works if you attached your iPhone to your Apple ID in the first place. The phone bugs you about it repeatedly but many people do not do so.
The only thing available related to the web interface accessible from that URL that is similar to that is that you can alter contact phone numbers (daytime, evening, and mobile) associated with your Apple Account, it doesn't say anything about iMessage associations.
So, if that's the way to do it, its interesting that:
1) There is nothing in the UI that indicates that it has that effect, and
2) Apple's own help page directs you to call support rather than doing that.
Then I fail to see why this is really an issue - blog explains no proper solution, need to pay $20, engineers can't figure it out, etc... Sounds like hogwash.
The OP has said [1] that he dissociated his number from iMessage and people who text him from iPhones are not getting through to him. That is problematic if you want to receive text messages on a non Apple phone.
It would seem he wrote in his blog in order to get help or bring it to a wider attention.
An antenna is defined by physical characteristics, not whether or not it functions suitably for a given application. A solution is something that solves a problem -- it is only a solution with respect to that problem, and only to the extent that it actually solves it. If it doesn't work, it doesn't solve the problem, and isn't a solution.
It is really an issue because the above workaround doesn't always work. You can apply that to every single suggested fix in this entire thread: it might work for one, but it doesn't work for all. The Apple discussion forums are littered with evidence of this, and my own personal experience of swapping back and forth a few times convinces me that people aren't just making it up.
Then isn't the real issue that the proper solution doesn't work? Doesn't the blog unjustly criticize Apple, as if they don't even have a single solution?
Sorry, just realized I am arguing over the formality of someone's self opinionated BLOG...I'll show myself to the door.
Seriously though, iMessage should have some sort of interoperability on other devices, even if its just a web interface you can log into to make configuration changes, including the deletion/deactivation of an account associated with a mobile phone number.
Edit: Or even monitoring iPhones associated with a number and disabling iMessage if said phone is no longer online with that number? Could possibly even forward unread messages, etc.