Because if obedient perfection was what God most wanted; then He designed us and the world we inhabit rather badly!
Therefore we must assume that obedient perfection is not what God wanted most:
...the potentiality of growth and development which can only come to us through the deep, tragic, heroic and painful experience which comes to us through the misuse of our godlike abilities, but which also registers in us the godlike remorse and the godlike desire to correct the mistakes we make as we make them.
So that great wisdom, whereas it will not force people into situations which it knows are incorrect and painful, at the same time will learn to wait for the individual to work out the results of such wrong engagement in life.
Because wisdom knows that it is only through the wrong engagement in life that some greater value than obedient perfection can arise, which is not an ability to be in perfect harmony with all the beautiful qualities of the divine nature, but is, in fact, the ability to know on its own account, to know for itself, to know objectively within its own experience, why the divine values are divinely valuable, and what the values are which detract from and destroy those divine values.
This is difficult stuff - because easy to misunderstand or misrepresent. In some ways, it sound so close to mainstream secular liberalism. But it isn't - because this view takes quite literally that this life of ours is designed by God - that its purpose was framed by God - that God is wholly Good - and so forth... all of which is in stark opposition to mainstream cultural beliefs nowadays.
On the one hand God surely wants us to be wholly Good and does not want us to yield to temptations - on the other hand we are not made, not designed to be wholly Good - and people sin all the time - even if they resist the worst temptations.
We are in a situation of extreme imperfection, we have been placed in this situation by God: is it plausible that he really expects perfection of obedience to his commands and desires for us? - Or something else?
What are we and this world designed for?
I seems likely that our experiences of life, our experiences of the multiple and endless im-perfections of life - are part of the plan - so long as they are repented: and we have also been give godlike remorse and godlike desire to correct our mistakes...
In a nutsehell: some people (probably you and me included) can only learn from our mistakes; fromm going wrong and acknowledging that we have gone wrong. For us, nothing else works. So this is exactly what we have been given.
The world and ourselves in it are superbly designed for what they are intended to do!
If we don't mess-up; then we did not need to mess-up and we have learned from our strength - and indeed we probably have a special role relating to leadership, example, responsibility...
But if we do mess-up - and almost everybody does mess-up, again-and-again with no end in sight - then that too is made part of the plan. The majority of people - those whose lives always have been and (probably) always will be a mess can improve, yes - and should try to do so.
But the fundamental problem of imperfection is not really eradicable with people made the way we are and in a world made the way it is.
A fully Christian - but grossly imperfect - life is universally available. For most people, most of the time, this will be a mess, a litany of errors, weakness, succumbing to temptations - but a repented mess.
THAT is the essence of the Gospel message of Jesus. It was the Pharisees who believed perfection was 1. necessary and 2. attainable (and therefore any honest man knew himself to be doomed) - it was Jesus who came with the good news that all could be saved without any exceptions.
Not by Christ providing a new power to be perfect, but because Christ's death and resurrection meant that repentance was given infinite power to heal all our recurrent acknowledged failures and flaws to live how we know He wants us to live.