We already have the leisure society - the bottom rung of the income distribution (in the US) lives in that society. People below the poverty line in the US work very little and have consumption and disposable income (after taxes/transfers) of about $20k/year.
I don't see a claim in those links that people at the bottom rung have $20k in disposable income. I can't imagine they even have $20k a year to begin with. Your claims are very different from my experience living close enough to that bottom rung to know people in it.
In the second link there is a graph entitled "Disposable Income for a Hypothetical Single Parent with One Child, by Earnings", which doesn't fall below $20k. Of course, it may not be correct to generalize it, and it is incorrect to present it as "per person" since it represents two people - parent and child.
Please explain how this supports your figure. I don't see it. Dividing the consumer unit "average annual expenditure" by the "average number of persons per consumer unit" per column there, only the top two exceed $20k, and only the top 3 approach $20k. It does all exceed $10k, but there's still 27 million households spending less than $15k/yr/person - where it would be more correct to say "about $10k" than "about $20k".