Because each sect had their own set territory. They couldn't go beyond their borders. This one sect didn't have access to water because the planets within their territory didn't have water.
This is making a mountain out of a molehill - no Kazon sect actually suffered from a shortage of water in any of the episodes. Thirst was an issue in "Caretaker" only, and exclusively for the posse of Kazon who were stuck guarding the one known opening into Ocampa city and couldn't go fetch water even from the next oasis over, let alone from the local asteroid belt.
The idea that there would be territorial problems with obtaining water as such is a silly one. When Neelix tells our heroes that "some have food, some have ore, some have water", he's clearly speaking of the excess that the sects possess and use for trade. It would be just as unimaginable to have a sect without access to
food than it would be to have one without access to water...
Nu-Khan lapses in judgment:
1) If he knew that the Enterprise was sabotaged, he should also have known that it was in order for it to be destroyed either by the Klingons or Marcus. In that case, why would he surrender to be destroyed along with it? Khan had no way to know that the ship would have been saved in extremis by the intervention of Scotty/and or Marcus daughter on board.
Khan wouldn't care about the ship. He'd just need access to his crew aboard that ship, after which he could depart in a suitably big shuttle, hijack the Klingon flagship, and proceed from there. He
was a man of means, only limited by Marcus holding his crew hostage.
Khan could probably also predict that if he managed to get himself caught alive, Marcus would rush in to do the job Kirk and the Klingons failed to do in time. Skip one step, jump directly to the one where the superman hijacks a flagship and conquers the universe.
2) When he told Kirk to open one of the torpedo casings, why didn't he tell him that it was rigged to explode in case of such an attempt? He didn't know that Marcus daughter would prevent the torpedo from exploding at the last second! Plus one of his lieutenants would have been killed in the process.
But the torpedo didn't explode, even though Carol completely fumbled it. A harmless squib went off instead; there demonstrably was never any real danger involved. Which goes well with the idea that Khan had to gut the torps of functional stuff in order to fit the people inside. (Scotty rambles about "fuel", but for a photorp, fuel
is warhead, at least in the backstage manuals.)
Khan probably programmed the torps to show all signs of impending Armageddon in case of tampering. Telling Kirk to ignore that part would just have taken away some of his sadistic fun.
I mean for such a genius capable of devising an entire ship completely new and way superior to any other ship in the fleet those are serious defects.
Parts of a well thought out plan, it seems to me. Play along with Marcus on this plan to draw Starfleet attention to the Klingon homeworld; make sure that said attention carries the special Khan-made long range torpedoes as the means of igniting the desired war; at the right moment, get hold of those torps; cease to be slave to Marcus and conquer the universe.
What went wrong? Nothing much, except Spock, who was no stranger to also thinking 47 steps ahead and did the switcharoo with the corpsicles and the explosives.
Timo Saloniemi