Why can't you have an infinite sentence?
"Turn left, then right, then left, then right, then left, then right..."
The above is an infinite sentence. It would make sense in an infinite maze.
When I wrote this question, I was thinking of
non-trivial sentences. Unfortunately, I can't really define what
non-trivial means ... there is a book that is entirely one sentence with 400,000 words. I was certain that grammar prohibited infinite ramblings since it provides the framework with which to convey thoughts. Most people have structured thought, not endless ramblings.
I mean, an infinite sentence to me is like a persistent thought on one subject. I mean, imagine thinking about a dog ... at every minute, of every hour, of every day, of the year ... for the rest of your life, you think about that very dog uninterrupted. That's an infinite sentence and that's not really practical except by way of subtle technicalities that permit it to exist in books that are a single sentence composed of 400,000 words.