The work of Piketty [0] and others shows that wealth inequality has surpassed pre-WWI historical maximums. The postwar "golden age of capitalism" has given way, from the 70s until today, to a neoliberal system that simply doesn't serve most people on the planet. It's an unfortunate fact that significant change happens rarely without large convulsions, e.g. after a major war, because I don't see this being sustainable…
I would not cite Piketty, Zucman or Saez who are the hardest fighters of the wealth inequality thesis as they usually mix political advocacy and have been criticized in their methodology and have been under a fair share of controversies. Btw I have grouped them because this is how they are usually treated, both by the fact they are all French economists but also on the fact they all push for the same inequality thesi…
I think it's important to separate the empirical and analytic part, to which you can apply objective criticisms, to the political part, with which you can agree or not but which should have no bearing on the former part.
Anyway if you want to be honest you can also link to Piketty's rebuttal to the criticism, e.g. http://piketty.pse.ens.fr/files/capital21c/en/Piketty2014Tec...