Except that, in most cases, even abandonware is illegal. In order for abandonware to be legal, you must own and have paid for the original and not be able to get use it on your computer. And there are still too many rules of when and when not abandonware is legal. I'll have to find the site again, and I'll need some incentive to do it, but I can link.

Still, if I want to download a MAME or an NES ROM, even if I have the game or standalone, I can't legally do that. That doesn't fall under the exceptions of abandonware. If I want to legally play these games on my computer, I have to get the proper hardware to copy them to my hard drive myself.