Curiosity about maintaining Yeast Strains more than 4 "generations"

I have learnt a lot reading the articles and threads on cultivating, preserving, freezing yeast (as well as wild yeast!) etc.

I can't help not imagine myself "hunting" for a wild yeast strain that would work better than any other strain in the horrid hot weather my beer suffers!

However, if used only for 4 batches (as for 4 generations) how would a home brewer preserve the strain he just discovered and could save the whole industry in case of global warming?

 

Laboratory controlled culturing selecting the pure strain and reproducing it. How they do it is beyond my knowledge.

Generally this is not within the realm of ordinary homebrewers.

4 is also an arbitrary number, many go 10 generations. There are some that can risk batches, and will go until it mutates into something nasty/different.

I make a starter with a new yeast a bit bigger than needed then freeze 4 vials. If I made 4 new vials when using one I can make 256 brews from the original sample in 4 generations.

 

I've gone ten generations just washing the yeast. I didn't use the method on the sticky (I'm gonna start), but similar. I was really careful with sanitation every time I handled it, and even wore a silk face mask, western style. I don't know if the mask actually helped, but it looked really cool.

 

I usually brew with fresh yeast strains at the start of the season and then bank them. Then I typically take a sample from a saved batch of yeast and step it up to pitch. In effect only using second generation.