Interesting article.
It focuses mostly on the use of trademarks to monopolize the presentation of a public domain character, strangling usage by independent artists. It effectively preempts copyright. You'll be beaten down by trademark infringement claims and never even get that far.
When large corporations build their revenue flow on characters that will eventually enter public domain, it means... they will never enter public domain.
My understanding is that copyright was meant to protect an author's
revenue during his or her lifetime, and for a period after. Then the
property would enter public domain, giving it new life and adding to the
cultural stew.
Instead, laws will be changed. Not only that, corporate legal teams will work to nail down and monopolize as much material as possible, including public domain characters.
They will bully and intimidate independent voices into silence, which is unforunate to say the least.
If the article is correct, corporations are just expanding their arsenal by misusing trademarks.
More on the difference between copyright and trademark
here.