So here is the thing, if you have a 'safety net' you really don't have 'scarcity'. These effects manifest in the presence of the stress that you can't "undo" or may not survive the decision you make. That is what pushes the decision down into the "fight or flight"/"survival" part of your brain which is very focused on surviving "right now".

The book's entire premise is that you can end up making decisions in that mode that end up having worse outcomes.

We joke about companies that make choices to survive to the next quarter that end up killing the company long term, but it is the organizational equivalent effect.

Using the winter coat example, make it winter, you're homeless, and you have exactly $60 on you and two coat choices. If you buy the $60 coat you have to figure out how to get more money to eat, which could not pan out and you could starve, if you buy the $40 coat you know you can eat at least for a little while before you have to get more money. So that choice is survival based. If you get the expensive coat, then the next thing you work on is replacing your money supply. It either works and you survive or fails and you starve.[1]

One of the interesting things about basic income programs is that it provides a safety net which allows people to make better choices because they are not in survival mode.

Another revelation for me was that I had not previously realized that while I accepted people making bad choices under the influence of drugs or alcohol, it had not occurred to me that survival stress could be just as debilitating!

"Why did this person do this thing? Oh, they were drunk." that was easy but "Why did this person make this clearly stupid choice? Oh, they afraid of dying." that wasn't at all understood by me early on.

[1] The reality will be somewhere in the middle but that is the nature of the human mind to see the worst outcomes as most probable.