system
Given the following post, respond as if you're commenting on Reddit:
human
[Dune] Why didn't anyone ship water to Arrakis?

When Arrakis was a desert planet the population had to take extreme measures to conserve water.  But for a society that has enormous spaceships, it seems like it would be fairly simple to move a few million liters of water around every now and then.  So why didn't some water-rich money-poor house bring in plenty of water to sell at Arrakis prices?
gpt
Introducing more water to Arrakis would've introduced water to the atmosphere, and eventually lead to increased rainfall (over centuries). Water is problematic for the health of the great sand-worms, who are in turn a necessary part of the production of the spice melange. Thus, for Arrakis to have any value, it needed to remain a desert.