If we had perpetual copyright, I suspect Shakespeare's estate would be worth several billion dollars.
Yet, professional comedians make good money. The best are multimillionaires.
The developments the author points out aren't exactly new or exclusive to this century. You can trace them back to the Industrial Revolution. The 19th century English novelists I read seemed to populate their novels with characters who did nothing but drink tea, read books, make smart quips and over the summer, play a game or two of cricket (hallmarks of the quintessential Victorian gentleman, I was told). You had people who read as a hobby, and people who 'read' (and write about their reading) as a vocation (Matthew Arnold comes to mind, as do an unending list of independent lexicographers, researchers, and scientists).
And extreme success isn't stable. You can fall from the top into nowhere-land at any time.
It's ironic that many engineers believe the arts are a soft career option.
http://www.openculture.com/2013/02/david_foster_wallaces_199...
So yes, Shakespeare would probably still be taught, though the plays would cost a bit more.
My point is that a world with Shakespeare under perpetual copy-write is different enough from this world that it would be very difficult to predict whether or not it would retain its status as a teaching necessity. It could very well be the case that we would be teaching modern renditions of folk tales instead. Or that someone else would write Shakespeare-style archetypes in a more accessible format, and we'd use that instead.
Everybody knows Shakespeare because everybody knows Shakespeare. Its hard to say exactly how much of that is undone by copy-write.
It wasn't until the printing press that artists could look to the public to pay for their artistic endeavors. Shakespeare wasn't wealthy, but he could get by thanks to patrons and a devoted paying audience. Chaucer, on the other hand, needed his patrons, while Lord Byron was independently wealthy.
I take the opposite message from all of this. It is nice to live in a world with such absurd levels of human productivity that people have the education and time for half a dozen "frivolous" hobbies. As a middle class person, I can learn carrot carving and wood turning and painting without expecting any financial gain, then stop at a free local art gallery on my way to hear some free live music at a bar.
Maybe the author thinks that the past was the time of greatness in the arts because the only people who could afford to participate in the arts were great.