In reply to the corrected question: "is buying used more ethical than to pirate and emulate?" Of course.
OP is assuming that the only interest that needs to be protected is the original maker of the game and not middlemen who drive up the price. But the game market (starting with the new release market) works on the same principle of buy at a lower pricer and sell at a higher price. The $60 game you buy doesn't earn the original maker $60. They had to pay royalties to the platform holder and sold to retailers at a price quite short of those $60. You could buy for a cheaper price if you were to buy directly from publishers, with retailers being eliminated, but when that actually happens (digital distribution) the price is closer to the one we're used to, because publishers use this new model to maximize their profits instead.
Because prices are determined by what seems acceptable. And that is largely dependant on the principle of supply and demand. Piracy creates infinite supply and severly impacts demand for legitimate copies. On the used market, rarity drives up prices. Piracy of discontinued titles might not (directly) impact the original publishers but it obviously does hurt the rest of the market. The market that buys from publishers. If middlemen cannot profit from the market anymore, they will buy less from publishers too. A thriving used market (despite lost sales of still available new titles) does indicate demand and determines the value of a brand, franchise or even the publisher and developer.
You may not like scalpers but what they're doing isn't immoral or illegal. Nobody is forcing you to buy from them. And there may also be cheaper used buying opportunities if you look around or wait. Don't condemn the whole market for the worst sellers (in your opinion, not morally). Sometimes your only option is to boycott by not buying (playing without buying is not boycott btw, piracy can be counted and indicates success).
Piracy of old games also indirectly affects the original publisher. When they do decide to rerelease it or simply because people who play games for free do not have a reason (at that moment) to buy other games, that are available from publishers currently. That is also the reason why BC is cut and services like PS Now are introduced. To encourage spending time and money on new titles and services.
So you may think, I would pay money for this game, if I could give it to the original publisher, but since I cannot it is okay to play for free. It is not, because the post publishing market depends on you having to pay the used prices, and because the publisher would rather you cannot play the old game and buy a new one instead. Or buy their rereleases (might also be a remake).
Basically when you have two choices and ask for which is the moral one, it usually isn't the convenient one but rather the one you don't like. That is why people have to come up with reasons why something "is not immoral".
But there is also the developer's interest to be considered. The publisher serves as a middleman too and takes a cut of the profit the dev could have gotten. The dev also might have liked to have a larger production run and to have reached a larger audience. So sometimes devs make statements that even condone piracy because they want to reach a large audience (even though that screws their partners, i.e. publisher and retailers).
It is a moral dilemma. You want to play the game (and the dev might want you to play it too) but you can't. Current right holders could do an affordable rerelease but they don't because it doesn't give them much of a benefit. That sucks, but obviously seeking a legitimate way of playing the game is the more ethical one.
This is where your problem is. No game is likely NEVER re-released. So say you pirate the Battletoads ROM and emulate it, play the crap out of it. Next month it gets a surprise release on the Nintendo Virtual Console or some Classic Rare Collection or something. You aren't going to buy that, because you just played the crap outta the game already, you are no longer in a Battletoads mood. So the company lost out on your money because you pirated the game.
Welcome to the world of abandonware. There are many more cases than you think.
Many games that were considered abandonware are now on GOG, aren't they?
