That is true, they use those topics to increase their number of posts for their bounty programs, so trashy posts go updated again. Those topics or questions usually just need a common sense to answer. Separating the newbies of course, but they should learn that before posting a new topic, they should have read first the rules and regulations in the forum.
If every member would just report 10-15 trash topics per day, the forum will be much cleaner...
And also, spammers would realize there's no need to open trash topics to post in it, because sooner or later these topics will get deleted and their post count won't increase...