It may actually have been a pandemic (that just means it spread quickly and broadly). It just wasn’t a serious illness. Probably, most people who got it didn’t even know it. Sounds like they overestimated the virulence.
Perhaps your statement is true on a general level. But for my experience, healthy adult no pre existing condition, hospitalized for 5 days with H1N1, pneumonia and dehydration. Still feeling affects today.
The 50yo female across the hall also with H1N1 (same bland medical history) was care flighted the next day to Ohio State University Medical Center, intubated, and passed away in two weeks.