Unfortunately I cannot read this article, because of the pay gate, but I can confidentily say that inequality is most certainly inevitable.
Inequality is the core concept which keeps everything in balance on this planet. Humans are destroying this planet by trying to achieve a utopian world of perfect equality. The only equality that we should strive for is equality of opportunity, but we can't aim for equality of distribution of resources as this would lead us into eating up our entire planet.
If everyone in this world would get the medical care to live until 100, if everyone would get fed with the same amounts of fish, meat, eggs, fruit, vegetables, etc. then we would pretty quickly end up in the tens of billions of human beings consuming everything around us until nothing will be left and we have killed ourselves.
Resources are limited and unless we can build more planet Earths at random will, then resources will always remain scarce and the only fair way to distribute these resources without looting everything to its extintion is to let all animals on this planet (including humans) compete for it. The strongest lion will catch the Zebra, the smartest human will afford a big mansion, etc.
Humans need to become comfortable with accepting the laws of nature which kept our planet flourishing for so many million years or we will put an end to it very quickly. No human has a right to anything. Whatever you are given is what you have either earned, stolen or you've been given out of mercy, but never because of entitlement. The sooner everyone can accept that fact the better things will turn out for us as a species.
Also it's important to understand that what's good for humans (today) is not necessarily good for humanity. It's good for humans to burn fossil fules like mad people to keep our homes warm in the coldest areas of the planet or to install energy wasting air cons in hot places which we want to inhabitate, but in the long run this is damaging our environment and bad for humanity. It's good for humans to fly everywhere and drive everywhere today, but it comes at a cost for humanity at some point in the future.
Humans are ego centric, self entitled and selfish animals which think that what's good for them today is good for us tomorrow, but it's often quite the opposite. The truth is, the more we live in animalistic conditions like survival of the strongest, the better it is for us as a species in the long run.