"My concern is that any form of power can be abused. When corporations get too powerful, one gets anticompetitive behavior."
Compared to the past, there IS no anticompetitive behavior these days. Yes power can be abused and in fact you can rest assured it always will be abused, it is human nature.
Your children's ages say that you are young. The young are generally always idealistic and that is a good thing. Experience, age and wisdom, however, teach you that that idealism is largely but not completely misplaced and unachievable That is why each generation achieves only a little of what the younger generation thinks it can and age turns you conservative.
Social crusaders only come to frutition if there is popular support for their cause which is why PETA and the envirowackos have gone nowhere. When a problem actually exists, there will be popular support. If there is no popular support, it really isn't a problem.