Shitposters mostly don't care about the odds to get informative replies for their questions, or posts, what they mostly care about are their weekly (pay per week campaigns) or daily (pay per post campaigns) quota. Sometimes, I saw shitposters reply to answer for their original posts, so maybe (just maybe) small part of shitposters care about replies to their original posts. It might save their time (seconds) to find new topic to join and spam if their previous posts got replies. Nevertheless, in general having replies or no replies does not matter with shitposters, whom usually even don't spend their time to read OPs, or just fews posts in the last page before typing their shitposts.
They even don't care to click on the "
Show new replies to your posts"!
It wil be very interesting if the Profile page has new line for: Total times you click on the 'Show new replies to your posts'. It might become one of useful factors to point out potential shit posters. However, this figure might contain several bias factors, but I don't think bias will be significant large, because shitposters will probably don't care to spend their time to click on that button to create fake statistics for their accounts. Instead, they are busy with their shit-post composing works.
Most of them just jump from thread to thread posting any nonsense they wasted 30 seconds thinking about until they fill their weekly "quota" of posts.