An open media bay in the middle of a cabinet is a small engineering problem, because it is the one place with no door to stiffen it and the one place where heat collects.
The stiffness is dealt with by making the two vertical divisions on either side of the bay full-height members that run from the plinth to the top in one piece, rather than stopping them at the shelf. The top, the shelf and the back are all housed into those two uprights, which turns the centre of the cabinet into a rigid box even though its front is open.
The heat is dealt with above and behind. A set-top box and a player both run warm, and warm air has to leave upward. So the shelf inside the bay is set back slightly from the front and the back panel behind it is cut with slots at high level, which lets air rise out at the top rather than sitting under the cabinet top and cooking the equipment.
None of that shows. It is the difference between furniture designed for electronics and furniture that electronics were later put inside.