Well, the way this happens to me is particularly related to one game. There was a game called Spartan 300 if I remembered correctly, it was too easy for me to complete and I took it for granted.
Seriously, I would be very interested in playing my old The Punisher on Sega but the problem is that I can't purchase the console again, I'm not sure it's still for sale here.
Seriously, it's not understandable why they do such, maybe they feel it's no longer important based on the lots of new games coming out, I can't really say.