The point of passing certification is that the first party (i.e. Sony/Microsoft/Nintendo) will grant the game publisher a license to use their IP in a limited capacity to sell the game. This license allows the publishers to use things in advertising like the console logos, images of the consoles, trademarks such as the words “Playstation” or “Xbox” or “Switch” and related accessories (e.g. “Joycon”, “Sixaxis”, “Kinect”, etc.). Without the license from the console makers to use these elements, any means of advertisement using them would be copyright or trademark infringement and subject to takedown notices, cease and desist letters, and even lawsuits.
Further, if anyone attempts to bypass the console manufacturers on the sales end, it is likely that the console manufacturers would retaliate by yanking any developer accounts and permabanning any console dev kits from connecting to the console development network. It would theoretically be possible to get around blacklisted developer accounts by reverse engineering everything, but the game still wouldn’t work with the PSN, XBL, or Nintendo Online.
It is possible to sell an unlicensed game (and some have done it in the past to a limited extent), but it is quite difficult to do so to any realistic degree without mentioning the name of the console the game runs on, console developer accounts and hardware development kits to build the game on, or the ability for players to connect to the console’s online network (and thus inaccessible features like achievements, multiplayer, patching, digital distribution, etc.).
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