The idea is to write a fifty thousand word novel in thirty days. An average of fifteen to seventeen hundred words a day for thirty days straight.
Doable? Yes, and no.
You can write two thousand words if you put the time in and put your mind to it. You have an idea, and putting it down on paper is the easiest task.
Most likely the quality of your words, sentences, and ideas won't even be close to the final product that you’re going to want to publish. There are some who can write a great novel in a month. These are experienced writers in their genre, and their focus is typically on the number of books they can sell and not necessarily on the quality of what they write. Don't get me wrong. You could write an interesting book that sells, and many writers do that. However, if you want an intricate plot and character depth, you will need to spend some time making it right, researching, and rethinking your writing. Those quick writers are also very familiar with the expectations of their readers. They can produce a book every couple of months and start selling them instantly. However, I would like you to notice the writers that are famous for their work. Most of them are releasing a book a year, and even sometimes skip a release.
Margaret Atwood published her first novel in 1969. To date, she has released only seventeen novels. The most recent one was in 2019. That is 0.3 novels a year. Of course, Steven King or Clive Cussler can write more than one novel a year, but for established, famous writers, this is more the exception than the rule. (Shh ... Some popular writers also have ghostwriters. They don't write all these books themselves.)
Yes, you can write a great novel or novella in thirty days, but I guarantee most participants won’t write anything close to publishable. It takes a long time to find your way as a writer.
What NaNoWriMo does is give you encouragement to write. So put your story on paper. Write it down, NaNoWriMo or not. The world wants your story, so start writing.