Of course, even if we do cultivate our characters we will suffer the fatal consequences, since character is fate; cultivating our character changes it, and therefore changes our fate, creating new fated consequences.
Those who believe in free will do not bother cultivating their character, because they do not understand that they are constrained by it.
Those who believe in determinism do not bother cultivating their character, because they believe it is futile since everything is predetermined, which represents a different kind of misunderstanding of the way in which their character constrains them.
The interesting thing is that those who believe we have free will end up with the same conclusion as those who believe we do not; they are on the same side. They are united against the Ancient Greek position that only by cultivating our character can we influence the main dynamo of our fate, our own naive character, cultivate it into something more worthy, something that might truly create a small space of meaningful freedom in our lives.
This is not a difficult idea, but almost no one in the Modern world seems capable of grasping it. We all let the terms of the debate about how much freedom we have in the world be dictated to us by those who think in simplistic, polarized ways, even though out of the range of possibilities we are effectively only offered a single choice in two guises. Idiot and genius alike find themselves completely fooled by this simple and misleading framing of the question of personal freedom, and argue back and forth about which of the two falsehoods is true.
The reason we are all stumped by this is the same reason we are all stumped by most things.
Just as there is no viable species anywhere composed of a single member, so too there is no such thing as an individual person, or an individual mind. Without the help of a cultural framework, a person cannot learn to speak a language, nor even to think in any meaningful way. Our culture is so much a part of who we are that it is more accurate to say we are a part of it. Cultures frame the world for us in such a way that only certain ideas are considered possible; everything else is truly beyond the pale for us. Although when young, or tired, or feeling playful we may toy with a wide range of choices, our serious debates inevitably fall back on what seems realistic to us, plausible, and that determination of plausibility is fundamentally an irrational process that is done for us by our culture.
Each culture rules out different swaths of reality as stuff that only crazies or extremists would believe; whatever pitifully small field of possibilities remain "plausible" becomes the range of allowable "responsible" discussion in that culture. Even more clearly put, even the narrow range of ideas allowed to extremists and crazies is defined by the culture; ideas outside those bounds are not even expressible in the culture's language without extreme wordiness, awkwardness, and distortion. No matter how rational we think we are, no matter how much the scientist, the iconoclast, the rebel, the outsider, the freethinker, the genius, nevertheless our range of "independent" thinking remains within the boundaries set by our culture, or cultures if we have been deeply enough influenced by more than one.
We cannot meaningfully cultivate our character to create some kind of personal freedom for ourselves unless our culture imagines the possibility for us, unless our language expresses it, unless it comes within our limited range of conceivable thought. The reason we cannot imagine a choice other than free will or determinism is that those are the only two positions allowed within the range of responsible thought; those who want to prove how smart they are may choose from refinements of determinism, such as nature versus nurture, so that is how they express their "individualism" and "free thinking," in the culturally approved way. We pick off our culture's menu of ideas and call it creativity.
Since the Ancient Greek position on personal freedom isn't on our cultural menu of ideas, it is quite literally inconceivable to us unless we immerse ourselves fully enough in that quite different, almost alien culture of Ancient Greece, and even then it requires enough immersion in the corresponding language to even be able to express the ideas clearly. When I write "character is fate" in English, I am misusing the words, trying to bend them enough to convey something they do not naturally convey because of their culture of origin (character used to be an Ancient Greek word, but in English we have long since smoothed down its rough edges to redefine it in terms we find more comfortable). I could write a book on the problem of what Heraclitus meant when he wrote that character is fate, and still most Moderns would be incapable of grasping it, whereas most Ancient Greeks would readily appreciate the import in the original language. Each language naturally expresses a different range of possibilities to its culture.
So, the problem.
To create some limited personal freedom we have to understand it the right way, so that we can understand why cultivating our character is necessary and what that might mean, but that requires the support of a culture that conceives of fate, character, and freedom in the right ways. Our culture does not, which is why we end up splitting into hedonists and nihilists, none of whom are free nor understands why not.
We also need a culture that supports our efforts to become better people. Without that, even those who through exposure to Ancient Greece or other cultures do stumble upon the right ideas about personal freedom and how to develop it are extremely unlikely to get very far in becoming better people. For example, in Modern culture the struggle to stay afloat financially trumps all other concerns, especially anything with as negligible market value as the struggle to become a better person.
So there is some pithy saying missing here, something to add to "character is fate," something about culture framing character. Maybe that is among the many things Heraclitus wrote that we have lost, or maybe it was so obvious to the Greeks it didn't occur to him to write it down. If we want to make it easier for people to cultivate good character, we need to find the words to help them conceive of doing so, and then we need to change our culture to make it possible.
Anthropoculture must be the highest priority for a good culture, a sustainable culture, but in our culture it is barely expressible.