This is a really weird take I keep hearing from people.
Let's say Covid-19 is equal to influenza in every way. That is a disaster. Influenza is one of the worst illnesses we deal with. If we now have another illness continuously spreading in the community equal in impact to influenza, which infects 35 million people annually, resulting in hundreds of thousands and sometimes millions of hospitalizations, and 30,000 - 100,000 deaths each year, that is an absolute calamity.
I don't think anyone thinks we're all going to die from this. But preventing this disease from becoming a permanent addition to the routine illnesses we deal with is a big deal, and people are worried about the necessary social distancing required to contain it.
> (b) that shouldn't really matter to us. Longer term, we'll have a vaccine and it'll be added to the usual seasonal flu vaccine package.
That's a very optimistic take. We have indeed become much better at developing vaccines, but it's not clear that we'll necessarily be able to develop an effective one for coronaviruses. You say that we'll just add it to the seasonal flu vaccine package, but we don't have effective vaccines for influenza. They mitigate risk, but the mutation rate of influenza is such that seasonal vaccines generally only provide a 60% protection, and some seasons much less. And we've been developing these vaccines for decades, with tens of billions spent on flu vaccines and research.
We don't have any vaccine against the common cold, despite massive amounts of research towards that. Most colds are caused by rhinoviruses, but about 15% are caused by species of coronaviruses. And we haven't developed any vaccines against them.