The primary factor here is that while Saturn is a large gas giant (size 75), its mass is 3.33 times smaller than Jupiter (size 90). Titan, at 20 units out is therefore well outside the area where radiation would be an issue. Rhea at 9 units out would probably experience some radiation effects, but not nearly what might be encountered at similarly placed Europa around Jupiter.
It would theoretically be possible to have a "shirt sleeve" moon in orbit around a large giant, but not close in (I'd argue anything less than 25 units out is dicey).
That said, Earth-like moons are a sci-fi staple, so we'll continue to see them in Traveller, Star Wars, Star Trek, etc. but unless what we know about moon formation around gas giants is totally wrong, habitable gas giant moons that aren't tiny water worlds should be a very rare bird indeed.
It would theoretically be possible to have a "shirt sleeve" moon in orbit around a large giant, but not close in (I'd argue anything less than 25 units out is dicey).
That said, Earth-like moons are a sci-fi staple, so we'll continue to see them in Traveller, Star Wars, Star Trek, etc. but unless what we know about moon formation around gas giants is totally wrong, habitable gas giant moons that aren't tiny water worlds should be a very rare bird indeed.