We may not need the publishers or the industry infrastructure, but I would argue we definitely need the artists.

However my belief is that eventually music and eventually film will morph into primarily a hobby or very small business over time.

The creation of art is a basic human impulse. Art of many types would continue to exist and flourish without the "publishers or the industry infrastructure" as we know them today. Far from needing government to underwrite economic inducements to ensure that, it would have to legislatively ban art and have stern policing of such bans to have any hope of eradicating art and artists.