Technology

You're being too literal with the term copyright. Fundamentally what copyright has always been about is preventing someone else using your work for their own gain without your permission. In that respect yes, copyright is critical in the digital age. The problem is that it's a compromise. It balances the rights of someone who has "purchased" a copyrighted work with the rights of the creator.

Generally the balance that has been struck is that as a purchaser you have the right to do anything that you want with a work except to sell a duplicate of that work. You can sell the work, so long as you no longer retain a copy of it yourself. In practice this means transferring rather than copying. How exactly that's accomplished gets into the weeds a bit if you start splitting hairs, but what's important here is the spirit of the thing, nobody is going to care if technically you both have a copy for some short period of time in the middle of the transfer process.

As for "copy protection" aka DRM that is and always has been complete bullshit because it is a fundamentally intractable problem. There's exactly one way to enforce copyright and that's the legal system, anything else is doomed to failure.

We also desperately need to prevent companies from using that monopoly to prevent older works from being available by having the copyright and not publishing the work

This is solved by limiting copyright to a short duration after which the work enters the public domain. If a company wants to squander a copyright by sitting on it for the limited time they have it that's fine but they're only hurting themselves. The only reason this is an issue now is because of the ridiculous century long copyright terms we currently have. If copyright was reduced to a decade you would never see this happening anymore. That said a safeguard should also be in place to prevent copyright being used as a censorship weapon by the wealthy. I think a "use it or lose it" clause that immediately enters a work into the public domain if it's not available for some period of time (maybe a couple years) would nip any potential issues there in the bud.