AnotherDilbert said:I doubt that more than 50% of all GGs within 500 Pc from Sol have at least one moon with large masses of easily accessible water or water ice that can be mined for hydrogen. How do you suggest that we test that hypothesis (with current technology)?
You're not making a hypothesis, you're just making a baseless claim with no reasoning behind it at all (plus, you can't test a negative anyway). You're saying "I think everything we know about how planets form is wrong and doesn't apply anywhere else, so I'm coming up with my own idea and haha you can't prove it wrong". And you're also displaying how ignorant you are about science too.
Almost every moon in the outer solar system (except Io) has water ice covering it in vast amounts. Their entire surfaces (and in some cases the entire moon) are made of ice, so there's plenty of "large masses" of it. While some may have nitrogen or methane ices as well, the "bedrock" is still water ice. Titan is covered in hydrocarbons that can be used for fuel too (you only need something containing hydrogen - methane, ammonia, hydrocarbons would work just as well as water or water ice). And then there's ring system full of ices. And KBOs. And Oort Cloud objects. And comets. Ice is EVERYWHERE. And there is no reason whatsoever to believe that this is unique to our own solar system.
I guarantee you that the vast majority of systems with gas giants in the outer zone will have some icy moons (probably many of them). I know this because we know how planets form, we know that moons form around them, and we know that ices will form where it's cold enough.
So either you can do some basic research and go learn something about how planets and moons form and how that applies everywhere since it's basic physics, or you can sit there and insist that you're right and ignore everything we know and claim that everyone else is wrong.