You are underestimating the importance of standards here. On a PC you will always only get a fraction of the hardware’s power, because there’s way more stuff running at the same time, not just the game, and because the developers can’t know exactly what hardware configuration every single gamer has.
On a console you can know exactly how much RAM you will have available, so you can design your content to use that amount of data and then stream it into memory that you reserve at the start.
If you do that on a PC you may ask for more RAM than the PC has or you may leave RAM unused. Or you can try to optimize the game for different specs, which costs time and money, so you won’t get the same results with the same budget.
You are underestimating the importance of standards here. On a PC you will always only get a fraction of the hardware’s power, because there’s way more stuff running at the same time, not just the game, and because the developers can’t know exactly what hardware configuration every single gamer has. On a console you can know exactly how much RAM you will have available, so you can design your content to use that amount of data and then stream it into memory that you reserve at the start. If you do that on a PC you may ask for more RAM than the PC has or you may leave RAM unused. Or you can try to optimize the game for different specs, which costs time and money, so you won’t get the same results with the same budget.