I wonder how many are bothering to take their first aid courses?

Yes I know what you mean about assembling the kits.
I tried putting together a few workable winter car kits a few years ago.
Just the basic stuff anybody driving in the winter should have in the trunk of their car.
They were pretty minimalist.
You can not sell such a kit to people who won't even take a winter coat or gloves with them when they know it is 20 degrees below freezing out, because even if they do bother to buy an emergency kit it will be the cheapest and most useless one possible to find.

I wish you luck with your venture.