What you're doing then would completey affect others. You are manipulating the market. Basically in it for a monetary gain aside from whatever reason you have to collect whether it be nostalgia or whatever. Whether you play the games or not doesn't take away the fact that you reduce the amount of copies in circulation. That drives up prices no matter how you cut it. It's just a matter of gaming morals I suppose. Another example is earthbound the cart is going for $120 and the game has never been ported. Not everyone can afford $120 on a single game and not everyone is going to find one in the wild. I'd say between it's high demand and the fact it has yet to get a port makes people revert to illegal emulation.
VGA is a even better example of the WTF just happened. VGA won't grade a game unless it's sealed.