What societal problems do copyright solve today?

Copyright as a set of policies addressed two major concerns:
1) It encouraged the authorship of work by providing authors an exclusive right to earn an income on their works.
2) It encouraged the distribution of work by protecting publishers' investments in dead tree printing.

Such policies successfully resolved the social problem of inadequate dissemination of knowledge through methods of knowledge distribution. The policies did not stipulate which knowledge would become popular and pervade the culture of the people, nor did it enable authors or publishers to tax the people for using published works in their culture. Hymns and ballads and poems and all manner of national or religious or popular literature were performed and adapted and remixed in public both before and after copyright protections without compensation to their authors, and everyone seemed amenable. Scientific and philosophical texts were likewise freely recited lecturers and students and whomever else, providing great incentives to earn an industrial and social currency. With the exclusive right to earn income by authoring and distributing works of good quality, authors, and the people all profited from the expanding commons of information.

Concern 1 was based on the assumption that for authors to earn income, they required exclusivity to the rights to duplicate their works.
Concern 2 was based on the assumption that distribution of works requires producing tangible representations of the information they contain.

Since neither of those assumptions holds for some modern works--anyone can write and publish a blog at no financial cost to themselves*--and social benefits can clearly obtain even without the protections offered by copyright, why do we continue to expand the scope of copyright protections to new forms of work? Certainly, there should be considerations of moral rights of authors relating to attribution and the artistic, scientific, and creative integrity of their works, however such rights should not and cannot be primarily defined in terms of distribution, finances, or methods to ensure scarcity.

The primary purpose of public policy should be the advancement of public good in some way. So what societal problems do copyright solve today?

If the goal of entertainment publishers is to influence popular culture, what is the purpose of litigating against those who subsidize the distribution of works of entertainment? Further, how do they derive a legal right to collect perpetual royalties from the ephemeral popularization of items they've injected into popular culture?

If the goal of software publishers is to enhance the public's well-being through their expression of mathematical algorithms, how do the publishers derive a right to to determine for the public which uses are allowable? ("Free" [libre] software licensing schemes do not escape this criticism. If the rewards to authors are claimed to be primarily social through recognition, reputation of the authors should have more protection than the integrity of derivative versions of the works.)

The social role of at least some modern creative works bear little resemblance to the roles of works originally envisioned to be protected by copyright. Policy around such modern creative works should also reflect that modernity.

*this is a deception that I will address in a separate consideration.

Order and chaos are not the only opposites.

Inspect your body as you would a building. Your life and the lives of loved ones depend equally on the quality of the building materials.

Seek not to own that which cannot be acquired in full.

The fume of eternity lasts but a moment.

[My apologies in advance if I unintentionally brick the universe.]

2**7 + 1

Manity remaindered.