“I can’t survive above 38.0 C for very long as well.”
OP must be weak. I had a fever above 38.0 °C for over a week once. Finally went to the hospital and my fever was gone by the time I arrived. Our bodies do some weird sh*t sometimes.
Also, you kill only half of them each time. For the sourdough starter, it’s like a Thanos-snap coin-flip everytime you bake bread. The bacteria in your current sourdough starter come from a long line of statistically lucky ancestors.
I suppose that’s kind of true for all of us, though…