I don't think the "Supermodders" are giving up so quickly....
Fact is they come from the SH3 scene and have learned a lot while struggling with it, so they are now much more selective and refined in their work. They are not constantly rushing to add all new mods and well-looking items, but instead have gained much wisdom and let new mods and improvements settle down and proof their value before adding them to their work.
As for GWX, they are still busy with the final 1.04 release of their work. Thinking about SH4 for them right now is out of the question, as it should be, but who knows what can happend when they end their SH3 adventure and have had some rest, maybe all or some of them move on to SH4. Have a bit of patience, man

SH4 is here for the long run, and you can be sure it will be turned in agame as beautiful as the modded SH3 is now....just note that for SH3 it has been a 2 years road, so Sh4 will have also its time