It's not exactly having the money/power which causes the destruction.

There are people (though in the minority) who have significant amounts of money and maintain their humanity and decency.

Money is power. The two are interchangeable. A person with money can get power, and a person with power can get money.

There are people who orient their lives around other elements (legitimate humanitarian causes, for example) but who have the ability to convince others to help them in their cause with significant money. There are also people who - through pure stroke of luck, usually through the birth lotto - find themselves with lots of money/power with no effort put in on their part. Some of these go on to be decent human beings and use their gift for beneficial purposes.

All this said, however, nobody who orients his/her life around money/power will maintain their humanity. The belief that money/power is the end toward which we should dedicate ourselves is indeed - as you are getting at - the root of personal destruction, the belief that the priority in this life is to accumulate money/power and then use it to change the world around us. Unfortunately, more than 90% of those with the resources to put them in the club of the rich/powerful believe their money/power is what defines them. And yes, those people simultaneously destroy themselves as they create the destruction around them that we witness daily.