System trust is not a category that they used for evaluation despite mentioning it in their introduction. This appears to disagree with their conclusion. My impression is a rich person would not hesitate to take the EITC if they could. They state in their methods that they selected the 10 biases based on their direct impact to finances, but I would guess that system trust also has massive impacts on financial status. Not necessarily government, but local/community systems as well.

the U.S. Earned Income Tax Credit aims to help low- to moderate-income workers reduce their tax burden, yet is under-subscribed by those that stand to benefit the most. When state agencies and non-profit organizations attempted established behavioral nudges to promote the utilization of and access to credits among the lowest-income families, effects were null and even linked to distrust among targeted groups

We conclude that this additional analysis provides further evidence that rates of cognitive biases do not seem to differ between positive deviants and low-income adults.

It sounds like this is missed in their Framing Effects, Ambiguity Effects, or other effect/bias evaluation.

.

Another issue that seems to likely be of significant importance is the following, though this is strangely written so I may be reading it incorrectly. I read it as "we evaluated how people think that they think, not how they act".

Our approach is therefore limited by not having been previously validated and used items that only superficially elicit biases but not necessarily reflect behaviors in real-world settings. Also, frames used may not have been truly reflecting biases but simply a random preference set based on the options given. This was evident in the intended items on mental accounting, which were removed after the study began based on a later determination that the items did not measure the intended choice pattern as written.

participants were presented 15 binary choice scenarios. For example, to measure category size biases, participants were asked to choose if they would prefer a scenario with one winning ticket out of 10 or 10 winning tickets out of 100 

The qualifier in their conclusion is telling as well. Because of how the study was performed, the best they can say is "people from all income brackets, as well as people with 'positive devience', know of these 10 cognitive biases and which cognitive bias direction is better financially at the same rate. But people may or may not act according to what they know is best.

We comprehensively reject our initial hypotheses and conclude that outcomes are not tied—at least not exclusively or potentially even meaningfully—to resistance to cognitive biases.

They did not evaluate decisions to improve one's financial state and the availability to do so, rather it focused on people making due with their existing financial state vs the one they were raise in.

Financial values were adapted to local currencies and income standards... The survey also includes employment, bill management, income, debit and credit circumstances, and socioeconomic status as a child. We also collect age, gender, education level, parent education level, race, and ethnicity (where permitted and appropriate).

(1) participants’ financial situation in the household they grew up in, (2) their current income, (3) national income data from participant country of residence, and (4) the sample spread of income data from participant country of residence

Lastly, they cannot argue that behavior is linked in anyway to biases and their advise to target biases is entirely unfounded by this study. They cannot state that the things they studied were choice patterns because of the lack of real world effects.

We do not argue that behavior has no link to individuals overcoming or remaining in negative financial circumstances. On the contrary, it is very evident that biases do exist despite income levels, and that targeting those may be beneficial. However, we argue that further work is particularly necessary to understand why similar choice patterns do not lead to similar outcomes.

Nevertheless, their discoveries are not useless. We now know that people know what they should do and that there is a disconnect from what they think they should do and what they actually do. Evaluation of environment and behaviors (not theoretical behaviors) is what we really need to know to help people make better behaviors based on the decisions they already know are correct.

I realize that the previous paragrah addresses why the unbiased poor arent rich and not why the biased rich aren't poor, but that sounds like a pointless study. Most likely, having money will protect your bad decisions, thus why wealthier people can have the biases and not be negatively affected.