The headline is a remarkably rosy spin on it when the subheading is "Research shows that ranks of higher earners have grown markedly over last 50 years, while lower rungs of middle class have shrunk". The article is behind a paywall but it makes it sound like inequality is increasing.

That's the whole point. When people hear "the middle class is shrinking" they intuitively believe people are slipping down a rung and joining the ranks of the working poor. The data doesn't back that up. The middle class is shrinking, but more people are moving up a rung than falling down one.

Which isn't to say that you're wrong about wealth inequality increasing. The share of wealth controlled by the ultra wealthy IS increasing, but the specifics of how that is playing out are nuanced and, at times, counter-intuitive.

But, Doctor, the data does back that up. The US middle class is shrinking, and most of the shrinkage is on the low end. There's no mystery about this, only potential for distractions.