will the 405th eventually die? yes everything has an end but the thing is when? well first off there will be 6 halo games( HALO1,2,3,Odst,Halo wars, and Reach) by some years, that means until all the games come out we will have more armor to build, you can still build stuff from the novels which i expect there will be more, so why people would keep doing props? well maybe some will make runs, make costumes for HALOween, for comic con, E3 and anniversary stuff so there will still be people who will join, and besides this forum is focused on halo but not only limited to it, leaving many more excuses to keep writing about, the only way that i see the 405th dead is if no one can take care of it(no mods,no admins= no forum) or any copyright massacre which would make us do everything scratch-made(which many people would still do.
quite a long reading but i expressed my thought...
Spartans never die neither the 405th!