Even if we were to accept the strong utilitarian argument, it doesn't really say that it's "required" to have a copyright system. Copyright is a means, not an end, and utilitarianism is about ends. Specifically, it's about increasing the total amount of happiness among people. Which isn't so different from the public policy approach, which is about improving society as a whole.

Neither of these systems hinges on the existence of a copyright system, and even if they did, there are many many ways to implement a copyright system. Certainly, you can't say I would argue that the system as it exists today flies in the face of both approaches. To understand why, it's necessary to understand the history of copyright. Both copyright and patents

Both patents and copyright were justified in a single clause of the constitution for the following purpose (and this quote comes directly from Congress in 1988):

"Under the U. S. Constitution, the primary objective of copyright
law is not to reward the author, but rather to secure for the public
the benefits derived from the authors' labors. By giving authors an
incentive to create, the public benefits in two ways: when the original
expression is created and ... when the limited term ... expires and the
creation is added to the public domain."

Or, if a quote from 1988 isn't interesting enough, let's look at a quote form the court in 1829, a date much closer to the initial creation of the Constitution:

"While one great object was, by holding out a reasonable reward to
inventors, and giving them an exclusive right to their inventions for
a limited period, to stimulate the efforts of genius; the main object
was `to promote the progress of science and useful arts;' and this
could be done best, by giving the public at large a right to make,
construct, use, and vend the thing invented, at as early a period as
possible, having a due regard to the rights of the inventor. If an
inventor should be permitted to hold back from the knowledge of the
public the secrets of his invention; if he should for a long period
of years retain the monopoly, and make, and sell his invention publicly,
and thus gather the whole profits of it, relying upon his superior skill
and knowledge of the structure; and then, and then only, when the danger
of competition should force him to secure the exclusive right, he should
be allowed to take out a patent, and thus exclude the public from any
farther use than what should be derived under it during his fourteen
years; it would materially retard the progress of science and the useful
arts, and give a premium to those, who should be least prompt to
communicate their discoveries."

This is about as utilitarian as it gets. The entire purpose is to help the public, the populace, society in general. Allowing for the perpetual monopoly of ideas, language, and art would be a crime against free speech and harm society. However, failing to protect it at all would provide 0 incentive for artists to create new work. So the most utilitarian balance is to grant protection to artists ONLY if they go through the copyright system, which would soon force their works into the public domain.

What we have today is an extreme perversion of this system. The content industries have become the very monopolies we sought to prevent. Copyright was originally 14-28 years maximum, but the content industries have successfully petitioned Congress to extend that to the entire lifetime of the author PLUS 70 years. And why not? They profit tremendously by doing this. But it doesn't help authors (who are usually long-dead), it doesn't incentivize the creation of new work, and it completely fucks over the public.