Are there any legal remedies for the writers of the web comedy series
keep the "yacht rock" term from being leveraged by parties like Yacht Rock Revue
profit from their original coinage
trademark their evolving definition/terminology
protect their future endeavors from similar behavior, which to me seems at least partly analogous to ...
Does this mean I can establish a de facto trademark by using the "TM" symbol without bothering to register it?
Not exactly. Your common-law trademark would be both de facto and de jure and would exist even in the absence of the "TM" symbol. The purpose of the symbol is to put people on notice that you consider it to be a trademark; whether it is or isn't ...
Penguin and Alfred Knopf are names of publishers or brands within a publisher. Trademarks indicate the source of a good or service. It is a brand. Your brand does not need to be well established when you first start using it. Rather than think in terms of a serise of books, you could make the name of the "publisher" something distinctive. To test if ...
First, what you describe as book “marketing” names are actually the names of the publisher of those books.
Second, a “series” of books is a group of books united by a common theme: the Harry Potter series, the Sherlock Holmes series, the Middle Earth series, the Jack Ryan series etc.