Neither of those became pandemic viruses though. And the specific year over year risk was essentially unknown until a new virus emerged at such point we had a couple of months to determine what we thought would happen.
That's the specific event risk: pretty obviously if we had maintained effective pandemic response measures, and maybe focussed on general infectious agent spread control measures as a society (i.e. a year over year goal to reduce influenza cases, update building codes to require less touchable surfaces to navigate) then we'd be better off then we are.
