>life expectancy in the US has declined by 7 months over the last few years and that our current life expectancy of 77 hasn't changed since 1997

Covid had a big impact on the last couple years, and the overall trend doesn't go up because for example obesity rates went up a lot since 1997. So while some people lived longer thanks to better researched treatments for cancer or other health issues, others lived less due to obesity so it cancelled out. Without that factor it would be around 83, which is where some other healthier countries are at right now. One good example is Japan, which seems to be going on a steady slow increase over time, from 80 years in 1997 to 85 now.