Con Artist is prolly to busy making money off of deadzone on facebook they'll prolly never make another laststand union city game or warfare game..sadly they were awesome and FREE
@ConArtists has created not one, but two immensely popular flash series (TLS and Warfare). Whether they decide to expand on one of these series, or create an entirely new one, is entirely up to them. As you said, Dead Zone is more than likely raking in quite a few bucks. Hence, there's no need for them to make a new game right away, at least until people stop playing Dead Zone.
But that doesn't mean that they aren't still in the process of creating new games. For all we know, we could see a new Warfare game within the next few years. Until ConArtists makes an official announcement about anything relating to a new game, we have absolutely no idea what they're up to. But saying that they're never going to make another game again isn't going to make new TLS or Warfare games appear out of nowhere.
Games are our life. When we're not making them, we're playing them. When we're playing them, we're thinking about making them.
While this doesn't prove anything at all, they don't sound like the type of people to just stop making games altogether because they're making a fair amount of money. After all, if they release a new game, they're going to make even more money.