I've been trying to understand a little more about this. The console that has thousands of games from systems like the NES, SEGA GENESIS and so forth. Apparently these are just sold by individuals on sites like Amazon, Ebay and so on. Are these illegal?
shareLegally it's a gray area. Abandonware isn't automatically public domain, but OTOH nobody's going to arrest you for using the obsolete. And if you actually own and possess the original ROM chips, you're not really doing anything wrong.
If you're in a position where you can't afford any sort of scandal, you can find lots of older games rewritten as new in clean room conditions that are 100% unencumbered. They might not be exactly like the original, but they're 100% legal.