Can anyone give me a good reason of why I shouldnt just go ahead and buy a Lee set up and be done with it?
Nope.
Just because you've never used better equipment don't mean you should show your ignorance of such things and put down people who happen to like better equipment because of more volume & experience.
I agree. If you need something better than a Lee to do more volume, get a Gracey or Giraud trimmer set up. These are both better than the Lee, the rest of them, not so much.