I for one don't do the vous, for the reasons you mentioned. I don't use a cooler, I eat period foods that are in my market wallet that are grown and dried (by me) meat that is harvested and dried (by me) use no modern amenities, I sleep with one 100% off white wool Witney blanket in period cloths that are handmade by me, I brush my teeth with wood ash, crap in the woods and wipe my rear with mullien leaves yatta yatta it goes on... Most people don't like my style of ruffing it, but it's all for my own experience and personal gratification.
One can be very HC if they want in a modern world. Thing is I see the vast majority of individuals on this forum anymore who can't distinguish the reality in it.
What I mean by that is we ALL live in a modern world in modern homes, drive modern cars, and shop in modern stores, some more than others. I grow allot of my food, I hunt for meat, tan my own hides and what have you for my HC hobby or "alternative lifestyle" just to name a few out of many. When we partake in our above mentioned alternative lifestyle the modern world is gone. I think there is much confusion as to what exactly historically correct is.
I partake in jurried events because I for one care about the authenticity, it's hard work but rewarding work, not for everyone and that's okay.
To end I've received allot of military training and have been downrange on multiple occasions as well, some of my historically correct standards have proven very useful and they do carry over into my daily life in more instances than not. I agree that allot of individuals would be very adversely affected by the lack of no survival skills for extended periods.
In short, doing period things in a modern world isn't hard. Just comes down to how obsessed are you?
To add, I'm planning a period trek this spring in garb with period equipment to traverse Mount Le Conte in the smokey mountains, anyone interested in attending?