Your question:

> What justification is there for using governmental authority to force Apple to make iMessage interoperable with any/every other chat service?

Justifications, in order of specificity:

1) Political philosophy: "government action is occasionally the only feasible or cost-effective way of bringing about an outcome which each person sees as beneficial - or would see as beneficial under idealized epistemic conditions - but which they lack the power to bring about unilaterally" [1]

2) Better user experience: "When a sector is extremely concentrated, the people who are willing to trade the public good and foundational democratic values for incremental increases in their employer’s profitability get a hearing within the company and take over the company’s decision making. When a business doesn’t have to worry about losing its customers due to abusing them ... eventually becomes a serious hazard to human rights." [2]

3) U.S. Supreme Court ruling: "The U.S. Supreme Court - just like the EU - recognized that interoperability was a critical user benefit that assured innovation and lowered cost" [3]

4) Legal precedent: The 1996 Telecommunications Act "sets obligations for incumbent carriers and new entrants to interconnect their networks" [4]

5) Proposed new law: "The U.S. ACCESS Act of 2021 mandates data portability from big tech companies." [5] This specific law didn't address messaging, but does address other services. Quite a few other anti-trust reforms have been implemented and are being discussed.

6) Department of Justice investigation: The DOJ is currently looking into "whether Apple is doing something it shouldn't be - blocking access to iMessage for reasons other than privacy and security." [6]

7) Current law: "The EU Digital Markets Act mandates that messaging services like iMessage are required to offer other companies some level of interoperability if they’re deemed to be big and important enough." [7] This law in Europe does exactly what you asked about, with WhatsApp and Facebook Messenger, forcing them to allow access from other clients. I don't know that anybody considers these as nationalized. Apple's iMessage is being reviewed, at this time it might not be big and important enough in Europe to be covered.

Shared values, legal precendent, new laws and the courts are how we collectively make decisions in constitutional representative social democracies. In practicality no further justification is required. If enough people want interoperability they'll eventually get it, like what already is happening in Europe, and is being talked about in the U.S. This is how our governments are designed to operate. Politics ends up reflecting the culture, and we don't live in an anarcho-capitalist society. That's not what most people want.

Do you have a position different than the above that you can speak to? Perhaps something that might persuade others to consider an alternate point of view?

Exploring this topic in more detail I'm glad to learn that the system appears to be in headed in the direction I'd hoped for. I'm content.

I'm happy to let you have the last word if this all seems like more vomit to you, maybe another pedantic zinger for old times sake ;-)

[1] https://journals.sagepub.com/doi/10.1177/1470594X13505414

[2] https://spectrum.ieee.org/doctorow-interoperability

[3] https://www.eweek.com/development/google-vs-oracle-scotus-ru...

[4] https://en.wikipedia.org/wiki/Telecommunications_Act_of_1996

[5] https://en.wikipedia.org/wiki/ACCESS_Act_of_2021

[6] https://www.msn.com/en-us/news/technology/apples-refusal-to-...

[7] https://www.theverge.com/2023/9/6/23861030/imessage-bing-eur...