There's nothing natural about Rogan. Look at him in the 90's before he got on roids if you want to see him as a natural dude in good shape. He was probably 150lbs then. Someone his height and frame size at 200lbs would look nothing like him without the HGH, roids, etc. Actual guys like 5'6-5'7'' that even have huge frames carry a lot of fat naturally at 200lbs+.
You said you're 6'3''. What would you say your frame size is? If you're one of the smaller framed guys, you'll never be huge in comparison to other people with larger frames/joints, but that doesn't mean you can't add plenty of size. What do you weigh now?