You’re conflating the purposes of copyright, patents, and trademarks here.
Trademarks don’t protect “ideas”, as a central objective. Their main purpose is to avoid confusion between market entities. Trademarks don’t, for instance, protect the idea of having an animal as a logo, but they’ll offer protection to ensure people know which animal goes with which company.
For a generic term to have any kind of trademark protection, it has to be distinguishably associated with a group, in the details, over all other possibly confusable groups.
Monty Python could only trademark “it’s” if it had other details that made it clear that it was clearly associated with Monty Python. It has nothing to do with the “idea”. They can copyright intellectual cultural output, even if it sounds similar to something someone else has done in the past or contains generic parts. Things like IBM, or CIA, or NASA, have a trademark-able aspect on just their initials, because 90% of the references in some fields are going to be the one organization and not the International Bodega Mavens. It has nothing to do with the “idea” of putting the letters “I”,“B”,and “M” together.
90% of the instances of the letters “THE” on clothing do not reference Ohio State University, so they’re not going to get protection on the letters alone, and they shouldn’t, because as you claim, they couldn’t want to stop other people from using the letters THE on clothing, which would mean the trademark would offer no way to differentiate who was confusing consumers, the main point of trademarks.
A good publicity stunt, but there’s no trademark argument there.
