Lawyers aren't expected to know the law outside of their specialty, but a law firm that doesn't understand basic trademark law is probably not a firm you want to trust with your legal matters, because it indicts a failure to perform even the most basic due diligence.

Lego already tried this approach and it doesn’t work. You cannot use trademark law to extend expired patents or copyrights.

The real ad here is them baiting Disney and running this fairly open and shut case. Of cause they can use public domain material in their commercial and Disney can’t prevent them.

To help understand your comment, are you a lawyer?