They learned all there is to learn about the nature of sentient life and the fates of the stars themselves.
Once a civilization has fulfilled the basic requirements for survival, it will inevitably seek to eliminate all forms of negativity and achieve perfection.
And therein lies its folly...and its downfall.
For perfection is an unattainable ideal. 'Tis the paradox of the immaculate carrot.
Yet civilizations since time immemorial have deemed the pursuit of perfection as “progress.” They pay no heed to the costs incurred in their futile quest, and all too often become the architects of their own demise, their dreams forever unfulfilled.
What, then, is the alternative? The answer lies in knowing that our existence can never be perfect. To be content with what we have and make the most of it.