I agree that a basic income is superior to current welfare programs in terms of efficiency, and also that an income of a level that could provide a middle class lifestyle is unsustainable at the present time.
However, I do think that a form of basic income is critical to the long term future of humanity. Eventually as our civilization's technology continues to grow, and we get technologies such as AI which begins to replace laborers and service workers, 3D printing which can eventually help us manufacture any items needed for cheap, etc, two things will occur. First of all, it will be more and more difficult for average people to have a job, because all of the normal jobs have been automated. Secondly, it will be less and less expensive to provide for the basic needs of a human being.
A basic income is eventually the solution to both of these problems. In such a future society where vast amounts of current jobs have been automated away, profits could be huge, and the cost needed to sustain a person at a reasonble level of life (I would say 'college student level') should decrease. When both of these things occur (some decades away), we will need a basic income system.
In my idea of a basic income, the funds for the payouts would not have to come from taxation. Instead, a fund would exist that was considered to be jointly owned by all people, that held capital, and earned dividends, and distributed these dividends to everyone.
This fund could be created by voluntary donations. Currently the rich spend a great deal of money on status items. If donating to the fund for humanity could be made to be seen as high status, some of these funds could make their way to it instead. It could be marketed as patriotic to conservatives (the fund that helps everyone in your country), or as compassionate to liberals (donate to the fund that will help meet the needs of all people).
The fund's holdings would need to grow over a very long period of time. At least decades. Of course, this makes it unrealistic in terms of current politics or as a short term solution.
Alternately, the funds could come from taxation initially, but be gradually phased out and replaced by dividends of the fund's capital.
Of course, this is not the idea that most basic income proponents talk about now. Its not realistic now, it is made for a future time. But I still think it would be good to start now, to get the world politically used to basic income systems. As bytemaster mentioned in the blog, they are superior to current welfare systems, and we could begin with a small basic income at a level sustainable at the present.
Just my crazy futurist thoughts on the matter.