Due to the weight of the cables, it's known that fiberoptic drones carry a smaller payload than wireless ones. The resulting explosive damage is less which is why they must be more precise in the weak spot they strike
Longer ranged drones require larger batteries which will have a deductive impact on payload weight. Larger batteries + larger fiberoptic spools will have more so. You can use a larger and heavier drone, like an agricultural drone, but such drones have l a higher risk of interception.
At some point for ultra ranged fiber FPV, it makes more sense for use on a winged drone which can carry a heavier payload than a copter. Hence we are starting to hear about fiberoptic Molniya drones.
As for SPGs, even for long ranged ones, they have been under threat from loitering drones for a while, and long ranged fiberoptic drones just adds another nail to the coffin. The Lancet has an observed or recorded range of 80km+, exceeding significantly its published specs. That puts even the latest longest ranged SPGs under direct threat. Now you also have Gerans with an optical tracking mode which have loitering potential.