You obviously do not have the slightest idea how the gaming business, or business in general, works.

Do you also hate id Software for not supporting Commander Keen anymore? Activision for not supporting Pitfall? Jazz Jackrabbit 2 is an old game. After a developer has finished a game, it will support it for a while, but generally after a while it will move on. There are simply no resources to keep committed to an only moderately-selling game for years afterwards while they could be working on new games. Would you not want to move on after working on a game full-time for over a year? Yes, you would.

As for "high-price patches", do you have any idea what it would cost to develop one? Salaries have to be paid too. With the current community, maybe 10 people or so would buy a patch (patches are in fact almost never sold, but freely distributed), which would simply not make it worth it to make one.

As for Jazz Jackrabbit 3, have you actually read anything about the developement process? Epic was pretty impressed with the product, but they could not find a publisher willing to publish the game. Well, that's the end of the product, as games have to be published to make profit on them, which is quite hard without a publisher.

As for the rights, those are divided between several people and companies, so releasing them in the public domain would first require (expensive) lawyers to arrange it all. If Epic would release the rights to the JJ2 characters or game in the public domain, no profitable sequel would ever be possible to create, so they obviously won't do that.

If you would've only spent a little effort to gather information about this all, you wouldn't have made yourself look like a fool by making these replies.