There's a small difference: "lifespan mobility" as you call it is not something where you see changes for yourself within your life - it is measured once, when

There's a small difference: "lifespan mobility" as you call it is not something where you see changes for yourself within your life - it is measured once, when you die. Income mobility affects you your entire life, and where you are is measured constantly. So no, it's not a good thing - because it means that if you're born poor, you stay poor. Calling it a good thing is the same thing as saying "more babies dying is great, it evens out the distribution to be more uniform, it's a good thing!" And no, the distribution is not "uniform". If you bother to look at the data at all, you'll see that it approaches a pareto distribution. Awesome if you happen to be one of the few rich or well-off. Sucks if you're one of the vast majority of people who barely make ends meet, and who are now, due to decreased mobility, stuck there for the rest of their lives. Decreased income mobility is only good for people who have a good income. And those are currently significantly outnumbered by people who don't. Traditionally, situations like this tend to end in war, revolution, or dictatorships. Really not what I'd file in the "good thing" category. The only way to make it a good thing is to increase the amount of people with a liveable income. Hence all the discussion around universal basic income going on recently. But until that (or some other kind of reduction of inequality has happened), reduced mobility is really, really, really bad.