No, there is abandonware, there are companies that really "abandon" their IP rights on old software officially, stating it on their websites, sometimes offering it as free downloads themselves. There are also download websites that emphasize the official "abandon" status of everything they offer. But other sites don´t, and of course those are much more popular.Also there is no such thing as abandonware, Its just another term made up by internet thieves to justify to themselves that stealing a piece of software beyond a certain number of years is somehow acceptable.
And then there are a lot of mixed cases. Things like Doom, Quake or Duke Nukem, where official versions are still sold, but shareware versions with reduced featuresets are offered for free.
@Dark Saibot: if you don´t believe that Mame´s intended function is to preserve old arcade games, how about checking the official statements? Why do you think they decided to pull back games already emulated for the sole reason they were too new? You might ask why they start working on games when they´re still new, but that´s simply more efficient, because the older a game gets, the more rare working boards get.
Concerning Border Down´s emulation: well, technically it shouldn´t be that hard, as there is a well-working Dreamcast emulator already. I don´t know whether the DC´s function of sending GD data over a coder´s cable also works with Naomi GDs, because otherwise they´d have to find a way of acquiring the data first. Considering the performance scale required by emulation, however, you will probably need a new, very powerful PC to get the thing running in acceptable performance. Just buying a DC with Border Down would be a lot cheaper.
