because R0 covid is 2 - 6 where flu is 1.4 < any measures made for corona would stop it dead in its tracks. for posterity's sake here is a picture with ranges:
https://cdn.the-scientist.com/assets/articleNo/67690/iImg/38...
data:text/html,<img src="https://cdn.the-scientist.com/assets/articleNo/67690/iImg/38474/uploads/what%20is%20r.png" style="max-width:100vw;max-height:100vh;"/>
Also, I don't see the annual flu on that graph.