Sorry, you're wrong.
r K theory explains abundance and scarcity.
It is a quantity (r) vs quality (K) issue.
r-selected organisms reproduce to maximize quantity, K-selected organism reproduce to maximize quality.
When there is abundance, r-selected strategies win, because even low-quality offspring can obtain some of the abundance and survive, so their greater numbers win.
But, that causes a decline in quality of the population of members of the environment, until the abundance disappears. Eventually the quality of the social body becomes so low, the population can no longer maintain the previous quality of life. Then, societal meltdown or, in case of animals in a natural environment, mass extinction occurs.
This is an ancient problem. Life quickly forgets that power ceases in the moment of repose.