Would you say there's any scale / level-of-necessary-ness at which a private party should acquire must-serve responsibilities?
Such responsibilities at some point seem an inherent consequence of running an economy where (1) companies are allowed to grow as big as they want & (2) "social" functions (i.e. services to all) are sometimes only provided by private parties (there is no government/public alternative).
And I really agree that the crux is "big enough" -- at some point, a phase change happens and regulation for social good needs to change too ('too big to be free'?).
We could pro/con public vs private-but-regulated management, but that's a dead horse and they're both valid options.
Such responsibilities at some point seem an inherent consequence of running an economy where (1) companies are allowed to grow as big as they want & (2) "social" functions (i.e. services to all) are sometimes only provided by private parties (there is no government/public alternative).
* Leaving aside the protected-classes argument