No one is telling you not to make new posts. It's just a suggestion to avoid topics like "wow, last night's game was great" when there is already a thread for it or "Travis Shaw is a beast" if there is already a thread about 3b or Shaw still on the front page.
Also, if there are limited resources on this website, how could one reasonably expect there to be a mechanism for daily site purging?
We are used to fewer threads because it's easier to track which conversation belongs where. When there are 4 different threads about Buchholz, it just dilutes the conversation rather than adds to it. As the great UN? once said, "bigger isn't always better, it's the motion in the ocean."
If you have a great idea for a thread, make a new one.