I won't patronize if you make a good-faith effort to address the question at hand rather than deflecting. The quote:

In short, convenience in entertainment and leisure do not necessarily mean widespread economic security.

Your arguments:

How about the air conditioning, that helps us sleep well and be alert at work?

Set aside for the moment the fact that air conditioning primarily changed the lifestyles of the south and southwest such that they were habitable and people could work. Air conditioning doesn't keep a roof over your head, nor does it put food on your family.

The penicillin and ambulance services, which reduce the consequences of health problems?

Set aside for the moment the fact that penicillin and ambulances don't keep a roof over your head nor put food on your family. Neither of these are available to you if you're poor. You think they are, but what happens is you get sick, you go to the hospital, you get treatment, you can't pay, and they garnish your wages. Assuming you have wages. There is a powerful financial disincentive against the consumption of healthcare that the middle class and upper class do not experience. Not only that, but you miss a couple days at Dunder Mifflin, you take it out of sick leave. You miss a couple days at the gas'n'sip, you ain't gettin' paid and you might be on your ass.

The poor spend money on entertainment and leisure as well.

Set aside for a moment...

A movie ticket in 1913 was seven cents. That's the equivalent of a $1.72 today. Meanwhile, movies cost between $8 and $15 depending on where you live. In 1929, you could see the Yankees play for a dollar, or the equivalent of $14. The average now is $34. On the other hand, first class on the Titanic was $4350, or the equivalent of $107k. And although Cunard is sold out of first class transatlantic voyages this year, midships is under a grand. So although your argument isn't quite "let them eat cake" it shares some traits.

But none of this gets to the matter at hand: does static wealth inequality matter? Piketty, at least, addresses the issue as a reason to not address the issue. The article you linked essentially says "never mind all that, the poor have refrigerators now." rd95 is arguing that having a refrigerator does not guarantee your ass won't be sleeping on a park bench a month from now and you said "how about air conditioning?"

HERE is a libertarian argument:

- If the poor today have experienced an equivalent boost to quality of life over yesterday's poor that the rich today have experienced over yesterday's rich, then the fact that today's poor are just as poor as yesterday's poor doesn't matter.

But you didn't make that argument, Piketty didn't make that argument and the author didn't make that argument. You want to focus on thirteen immigrants living in a chicken coop. If you're going to do that, we could drag stuff like this out:

...and I'll point out that the 3 bedroom house next to my old apartment that had fifteen illegal Chinese immigrants in it.

The question is not "are the poor materially better off now than before." That's an obvious yes. The question is "are the poor comparatively better off now than they were before" and Commentary magazine don't give a fuck. rd95 does.