A capitalist economy needs the government for some very key laws like upholding private property rights but how does that extend to "mandating interoperable message systems"?
The definition of "free market" includes being free from monopolies.
If the government wants to maintain a free market, that means they need to step in and prevent monopolies, which includes preventing anti-competitive behavior.
Apple is being very anti-competitive with iMessage. It's not just the blocking of Android clients, but the fact that Apple will not let you use any other SMS app on iPhone, so users are locked into iMessage.
By simply looking at the general state of the US economy that has lost competition across the board over the last decades as large companies consolidated to form extremely large behemoths that dominate their respective markets (e.g. Boeing for aircraft, Microsoft for computer operating systems and office software, Meta for social media, Walmart for groceries, Google for search, Cargill/Tyson/JBS in agriculture, AA/Delta/Southwest/United in airlines), use both legal and illegal (such as wage collusion) tactics to cement their marketshare, and extract ruinously low purchase prices from their vendors. This shit used to be different, with lots of competition and resulting innovation, not even a few decades ago.
> A capitalist economy needs the government for some very key laws like upholding private property rights but how does that extend to "mandating interoperable message systems"?
Easy. Apple has a very popular product that they (ab)use to push its users to push their friends to get themselves iPhones. Breaking up their stronghold over iMessage would allow Android users to communicate on their devices with people who own iPhones, and it would lead to a flurry of competing messenger applications.
A capitalist economy needs the government for some very key laws like upholding private property rights but how does that extend to "mandating interoperable message systems"?