Why doesn't God fix it?

In times of poverty, famine, natural disasters, crime, violent occurrences, etc. nonbelievers will ask "If there is a God, why doesn't he fix it?" or a believer will ask "Why doesn't God fix the situation?" I won't attempt to give God's answers to these questions, but I have my own hypothesis.

I think God doesn't step in because a miracle isn't needed in a lot of the situations that plague the earth. Humanity has the means to solve many of the world's problems, so why should he be called upon to solve a puzzle that we created and can solve? Poverty is man made. If humanity started to really walk in love, setting aside greed, and help people, the instances of crime, homelessness and poverty would go down. In countries where 10% of the population have 90% of the wealth, its obvious that a different distribution of funds could help those less fortunate.

Even in many cases of natural disasters, these things are caused by the damage that we have done to the earth over these billions of years.

Its in humanity's power to fix things, and the problems were brought about by selfishness and greed of humankind. This isn't absolute, but its relevant in many instances. God works through people, and if people are unwilling to do his good works, then good won't be done.