I really do not believe the hobby is going to die anytime soon. As Craig mentioned, now is a great time to be a model builder. We have better kits, the aftermarket, better supplies, great new kits from Mobeius and RM and companies like Round 2 keeping the old stuff alive for you nostalgic types. We all have our reasons to build, Like alot of folks here, my dad passed it on to me. Over the years I have come and gone from the hobby but I still enjoy it while I can. I will share it with my sons, nephew or anyone else for that matter that has a interest in learning more. I try meet with my local model club once a month if time permits to learn from them, as well as hanging around on this and the "other" forums to learn more from the seasoned vets.
IMHO, kids today really just need to be instilled with creativity. Get them to put down the cell phone and video game controller and go stone age on them and sit with them, and draw, build a model, sculpt clay... whatever. The little ones in my life do not need to carry my torch on.But it makes me smile that they have an interest in what I am doing. And as for adults, you never know who is a model builder out there. There is no accuate representation of who is building out there. There is no modelers census. But the manufactures are doing well enough to bestow new stuff on us that most of us want to spend our hard earned dollars on. The health of our beloved hobby seems to being doing well. There is light at the end of this tunnel and to me it's bright.