There is no constitutional entitlement to receive government information through one's preferred newspaper, website, or social network.
> it is a de facto loss of free speech for everyone else.
You seem to be confused about what 1A is and what it guarantees. It is a restriction on government action against your speech, not a general requirement that everyone have equal access to every privately owned communications channel.
OP's point is that creating a favored restricted platform natrually allows for restricting of free speech because of a private "compnay policy". ("allows for" is doing heavy lifting here btw)
Should a government choose to communicate essential facts only through a restricted medium it is obviously no longer serving the larger public interest and thus no longer a government of "a people for a people".
Musk and fellow techoligarchs can have their private platforms.
Free peoples' governments and responsible social organizations must treat them as 'for profit entertainment channels' and not give them any legitimacy in the political space.
> it is a de facto loss of free speech for everyone else.
You seem to be confused about what 1A is and what it guarantees. It is a restriction on government action against your speech, not a general requirement that everyone have equal access to every privately owned communications channel.