I think the simple answer to that is that flu deaths are now controlled by a vaccine and also to some extent by a herd immunity.
Coronavirus is not at present controlled by a vaccine and we have not yet had it amongst us long enough for there to be any herd immunity.
That means until we have those potential controls, we are vulnerable unless we follow the medical guidelines.
There is now a new venture which seems to be attempting to exercise some control by using antibodies from those who have had the coronavirus and recovered to inoculate those who are at risk. That seems to be a temporary procedure to stem the tide until a proficient vaccine is able to be used worldwide.