a homebrewer's concerns regarding a possible complete collapse of our civilisation

Okay so lets just imagine that it all goes to shit. Everything. No utility grid. No groceries. Supposing we survive- how will we have beer?
Pygalgia says he can carve up a dead critter pretty good. Super! Dead critters will probably be ubiquitous after a stupendous crisis-say,a calamitous sudden plunge back to the bronze age or something -the skills to make 'em dinner will be in demand.
How will we have beer when all the taverns and homebrew supply stores are long gone? Hmmm. Frankly, i find such a scenario terrifying, but maybe i shouldn't... as folks all over the world have always managed to contrive fermented beverages for 10,000 years or so.

I need a grain. Preferably barley. The barley must be sprouted i.e. malted by soaking and rinsing the husks in cool rainwater (assuming it rains) saving half of it for gruel, and half pressed into biscuits and baked at a long low temp (perfect for campfire coals) . Both the sprouted gruel and the half baked biscuits are spooned into a wood or stone lined trough and mixed, as hot rocks are dropped strategically into the mixture.Refer to picture above- this is neolithic style mashing!
Sprouting barley activates the enzyme diatase, which converts the inherent starch compounds to maltose- a basic sugar necessary for fermentation. The reason why half is grueled and half is baked is, the biscuit maneuver facilitates still more enzymatic activity necessary for fermentation, while the barley gruel provides lactic acid which inhibits nasties while somehow attracting Saccharomyces Cerevisiae- the yeast we want.
Now comes the tricky part... How do we get yeast? The homebrew shop, with its neat little vials of beer yeast around the world, is perhaps a smoldering ruin. Seems shaky to me, but the tried and true i.e. 10,000 year old method is simply to toss wild fruit skins into the wort. Grapes, preferably. Maybe i can find some in some canyon. More likely apples.
I have nearly exhausted myself, attempting to research where to find Saccharomyces Cerevisiae in the wild, at this latitude/elevation/eligible flora. 7000 ft desert is not a "fruity" place.
But some folks in Peru, even before the Mayans, had large-scale breweries at 10,000 ft. Apparently, they collected yeast from pepper trees.
We will figure it out, won't we? We always have.