I think you're exagerating the amount of configurations developers deal with. Motherboard version is largely irrelevant. X CPU, well, if the software is designed to scale on the amount of cores, then the only concern is if the CPU is fast enough to execute what you need it to. Well, its the same with single threaded games but I would hazard a guess that most AAA games are capable of scaling. As for videocards, its largely about what feature set it has, and many of them share the same feature set, within similar performance brackets. So its more like they are looking at groups of videocards rather than each individual one.
Since PC games tend to have a set of options you can fiddle with, if the game doesn't run smoothly at one of the presets usually you can adjust it to perform better on your particular machine. Not all games do this but you can safely blame the developer/publisher for this.
As for modding consoles, people who don't know how exactly can easily get it done at a local modding store. I think its fair to say that if you are aware your console can be modded to play burned games then it is likely you are aware you can pay someone to do it.