From another perspective, the total income of US persons in 2010 was over $12 trillion/year[1]. People are currently paying a total of $899 billion in federal income tax. Assuming we distribute the burden evenly per dollar earned, assuming incentive to work is linear in dollars, and assuming there are no other effects we would see incentive to work drop by something a little over one third. This leaves dramatically more incentive than the above numbers would indicate. For the record, though, $14k/yr is about twice the BI level that I personally (tentatively) favor.

[1] https://bber.unm.edu/econ/us-tpi.htm

[2] https://www.jct.gov/publications.html?func=startdown&id=4363