The TES games cannot have online games for many reasons. one is they want to spend their time making he best single player game they can. If they took time to make their games with online interactions the main game wouldn't be as good. Also the quest and radiant system they use now wouldn't go well online because of the randomness. Also Bethesda supports the modding community. This would cause glitches in online play because if one person has a mod and you don't the mod would cause major lag the only way to prevent this is to stop excepting mods or mike it so you have all the mods as other people in the server. Neither of these are ones Bethesda wants to do. So with these reasons and all the other ones online play becomes an idea that would be a hassle for both Bethesda and people playing the game. All in all it's just more work than it's worth.