Sony's magic trick is scaling production. The drive itself is likely shared among a few of Sony's bluray players, and that likely makes it the weakest link but also easiest to find a replacement for. The rest of this is licensing and computerization/internals. They're low power devices so there's not much to wear out over time compared to an amplifier or sub, something that draws much more power as part of its function. Sony will sell twice or twenty times more units than Oppo, partly because of the lower cost but also their existing supply chain presence in retail and online.
I wouldn't say there's huge margin for the Oppo, but they likely make more per unit because of the increased price. Their R&D is likely more costly as a proportion of the unit's production cost versus say the Sony model, because Sony can leverage (spread) its existing R&D and tech across multiple products. Not sure if how I'm explaining this makes sense. Also, supposedly Oppo has top notch tech support and that adds to the cost keeping a team on the ready to handle issues correctly and in a timely manner for customers at a random moment's notice. So you might get 'more' with the Oppo, but whether that value is worth the cost is for each buyer to decide. With fail rates while under warranty being low on these types of electronics, I wouldn't personally put much value in Oppo's support as part of my decision making (hence why I went with the budget option X800M2).
These increased costs for Oppo to accomplish the same things as Sony could lead one to conclude that their mechanical product is of the same quality in order to keep the production price relatively reasonable (but possibly still more expensive compared to Sony due to increase costs for basically the same components that Sony buys in huge volume), and the whole "premium" label on Oppo's models are just hype and marketing. It wouldn't be the first time a 'premium' product in the audiophile realm was just another overpriced thing.
Someone would need to do a complete teardown and research all the parts within an Oppo to know just what each player costs, or to confirm it's all similar quality components as any other player. Not something I've ever felt I needed to look into, so this info might already be out there.