A confounding factor here is that savings behavior is cultural rooted: https://pmc.ncbi.nlm.nih.gov/articles/PMC6135367/. Studies show that people within a country can have substantially different savings behaviors, robustly correlated with their origin countries, even among people who are third generation immigrants. It’s a mistake to treat either the U.S. or Singapore as homogenous populations for purposes of this analysis.
I once heard a linguistic explanation for this.
European languages have a future tense, which means people have different ideas of themselves in the present and future. You can even hear this in phrases like "that's a problem for future me."
While Chinese lacks the European styled future tense, ignoring time phrases, auxiliary verbs, etc. So people more clearly conceptualize their present and future selves as the same. Leading to things like increased saving.
This of course is rooted in linguist psychology, a very soft science. But still an interesting idea.
75% of Singaporeans are ethnically Chinese so based on what you are saying it would be worth comparing SG Chinese to Chinese CN on regret since China has a much less robust safety net.
Both sides see declines when hit with economic shocks
We are talking about material impacts, not culture