You are right, we can only speculate what a world without copyright would be like. But I think it would be a fairly boring place.
Well, copyright didn't exist until the 18th century, and then didn't become widespread until the 19th and 20th centuries (in many places, due to colonialism, rather than because the local population liked the idea).
So now you have a pretty good idea of what it would be like.
Of course, you'd have to factor in differences unrelated to copyrights: many places have less censorship than they once did; they have higher literacy rates; they have publishing technologies that are far more efficient than what was available when they adopted copyright laws, including the ability to publish sounds and moving pictures, which had not been possible; we have artificial lighting, inexpensive and widely available means of telecommunication, and data capture, editing, and storage technologies; improvements in agriculture, manufacturing, and labor law provide somewhat more leisure time than once may have been available; the population has increased (thus increasing the number of actual and potential authors); etc.
Wile I think that we're better off with some degree of copyright than none at all (though probably less than we've got now), I think that a world without copyright would be okay; not optimal, but okay.
I enjoy watch movies that were made on a $100 million dollar budget. They tend to be better than movies made on a $10,000 budget.
I think that what matters is the writing and the performance, not the budget. I saw the play version of Driving Miss Daisy before the movie came out. The play had three actors, and usually the third wasn't on stage. The set consisted of a couple of chairs and nothing else. The actor playing Hoke (the driver) had to hold his arms in front of him and pretend that he was steering the car. It worked fine, and everyone enjoyed it. The movie added real sets, real cars, location filming, a number of additional actors, and wa fine too, but it didn't need to. It would've been just as good had they filmed the black box stage performance, like the movie Dogville.
Also IIRC, there was a low budget (I mean really low budget: http://starwarsblog.starwars.com/index.php/2008/12/19/star-wars-live-on-stage/ ) that went over well. While multi hundred million dollar movies with bad writing and bad acting like this year's The Lone Ranger, get to go directly to the trash. Big budgets are not necessary.