I think it will come sooner than we think, and no matter what "it" is, all we can do is hone our skills and prepare as best we can. DH and I expanded our garden, expanded our library, and have a few other "skills" in the works. All in all, we started this adventure/change in lifestyle not for if or when SHTF, but because we wanted to get back to a simpler life....but thats a different thread
I like your attitude PG, the simple life is the best way to go, if one is living it daily the coming SHTF just won't be that big a deal.
To most Americans a day without a latte is a SHTF day!! for most kids not having a Play Station is a tragedy of horror!! for most discovering the Microwave is out is truly a SHTF, how will we eat??? we can't cook our food!!!!

Folks in a lot of the US really weren't bothered by the Depression, my mom said they were so dirt poor they never noticed it start and were still so poor when it ended they never noticed it was gone.
I said just the other day that if nothing else we can live on eggs and tree rats, not joking!!!.. I think that day we had 21 doz eggs in the fridge, all free range eggs...the best kind... I gave away most of them to friends, now there is 17 or more dozen ... this is truly a SHTF!!!
If your growing your food now and living simple you will be light years ahead of 98% of the rest... keep your head down and don't make waves and your going to be alright.
I've ceased worrying over nukes, if they come I'll do what I can but that's it, I believe not owing money and living simple will help when the Monetary SHTF comes home to roost...
A financial collapse has the potential to drop the entire world to it's knees then we humans will finish the job with riots and war between ourselves fighting for scraps.. and it could happen over night .