Because it is nothing more than a myth. Even if it were true, a perfect life would be most tragic nonetheless.
For perfection is an illusion seldom held in place for very long. It might be here today but it’ll be gone the next tomorrow.
Because in the end, perfection is okay with it’s own imperfection even though you and I have difficulty in accepting this reality.
Every conscious being has only their personal understanding of the universe with which to operate. If that being is rational, their mind works in rigorous hierarchical order with what it perceives as being real (existential), probable (theoretical), or possible (potential.) Your personal or usable version of the universe is therefore limited in its scope by your knowledge of the infinite universe’s possibilities.
To put it another way, only things that you can at a minimum conceive of being possible have any significance in your personal universe. Therefore, your knowledge of the infinite universe limits the size and scope of your personal universe (Michie, Jim. “Self-Realization, 2012).
It is far more conceivable to imagine ourselves as being set perfectly in place than it is to think that we with our limited scope of awareness, attention, energy, intention, and understanding can achieve perfection. To do so would require far greater or an ever increasing level of control over factors outside of our personal universe. Even if this is a finite possibility, we have yet to discover the rules by which this might be made possible.
So, the only remaining question in my thinking is whether or not we can be happy in our current state. This is our choice as limited as it may be.
Such happiness may in the end be an important prerequisite in the journey towards more greatly perfecting our existence. Although a healthy dose of tension may need to be sprinkled into the mix from time to time, complete chaos, major friction or trauma, having one long pity-party for ourselves, this to me looks to be hugely counterproductive at best.