When I think about issues like this, I like to make believe these men had never existed and imagine what would have happened. There is always some of what we have come to call "class envy" when we think about those who have "made it" --- the rich. There is also the fact that some of these men, particularly Morgan, may not have been among the kindest of men. But I suspect they are just the people who happened to be there and who made their industries work. Were it not for them, someone else probably would have done the work. But while they were accumulating great wealth for themselves, they were creating jobs for many and creating the industries we needed to make America a great economic power.
I think some of what they did would have had a permanent negative effect, but the other side of America took over, this time in the person of Theodore Roosevelt who "busted" up some of the trusts and left a lot of the good they did behind. And the rise of the labor union movement built on the empires they had created and shared more of the profits with the workers who created most of the value. So, in one sense at least, it worked out for the good of everyone.