You are misunderstanding the article. The study asked some rich people "would you spend 30 minutes to save $50 on a $300 item". Some rich people said yes. Then

You are misunderstanding the article. The study asked some rich people "would you spend 30 minutes to save $50 on a $300 item". Some rich people said yes. Then they asked "would you spend 30 minutes to save $50 on a $1000 item". Some of the previous "yes" answers changed to "no". That is illogical, logically no one should have changed their answer. Poor people didn't make this illogical answer change.