I’m sure we’re the best overall but there are quite a few events where we’re not:
800: 1 total medal since 1996 (bronze). Kenya has won the last 5 gold medals (4 different guys), last US gold 1972
5000: last gold 1964, zero medals between 1968 and 2012.
10000: last gold 1964, 2 total medals since 1968
Marathon: last gold 1972, 2 total medals since 1980
Discus: no medals since 1984, last gold 1976
Hammer throw: no medals since 1996, last gold 1956
Javelin: no medal since 1972, last gold 1952 (only one ever)
https://en.m.wikipedia.org/wiki/List_of_Olympic_medalists_in_athletics_(men)