Replying to Delete your own threads

so i made a thread today as a WTB but then i realized that i need to save money for other things such as a car not purchase a new hoodie.

anyways, my question to NS is why cant the creator of a thread delete it?

If they made it and messed up the thread shouldn't they have the power over their own threads.

Also, if this isn't possible just a quick explanation would be nice

thanks guys!