This is true. There could be in-universe explanations for jump drives becoming too problematic or unreliable to use, though, related to the evolving difficulties with jump gate shutdowns and reorganizations and such. Since jump drives (at least in X3) depend in a crucial way on the jump gates (even when jumping to beacons; otherwise why would the cost depend on number of gates traversed), disruptions to the jump gate network (like a jump gate firmware update XD) could potentially make them unusable by the TerraCorp variety of jump drive. If the jump gates were put in place and are still managed by inscrutable, possibly beneficent observers, intentionally ruining the TerraCorp jump drive interaction with the jump gates makes a whole lot of sense: functional jump drives are militarily destabilizing as they make every place vulnerable to attack. Godlike managers would want a military paradigm which is less prone to wild swings in fortune.Nanook wrote:The original theme of the game universe was a jump drive failure that lead Kyle Brennan to discover the X universe. Making them disappear in the game denies the original lore of the game. The X universe without jumpdrives just isn't the X universe.
The disappearance of the Rebirth jump drive is a little more difficult to justify in such a manner, but perhaps a few high profile collisions at beacons could do the trick to convince authorities that beacons should be taken down. Or perhaps their use by pirates or Xenon or other hostiles could also contribute to that impulse. Safety and security concerns mixed with the ascendance of competing technologies.
But that still leaves the unfocussed jump drive. Hopefully that exists in X4. It poses no particular problem to gameplay; you jump to a random place unconnected to the gate network (because the universe is vast and 99.999% of it isn't anywhere close to the gate network) and then jump back. As far as travel within the sectors connected by gates is concerned, it doesn't actually move you anywhere.