I find it striking how many of the blind spots wrt the web have been a feature of ASP.NET since the beginning: static file serving, caching, authorisation...
If you're saying these things are "missing" from aspnet core then yes -- it's by design. All of this is handled through middleware, the same as in NodeJS. You can very easily create aspnet core projects with all of the above but MSFT isn't making overly dogmatic opinions about how you should do each of those things or even that you need to use their solutions for each.
They’ve literally just launched a library that adds conventions to Swashbuckle. Not saying it’s not useful, just that serving static files probably ought to be higher on their priority list.
How do you mean?
I've done a few projects using ASP.Net Core and they've used all of those
It's not that you can't, it's just that there are some short comings that many will quickly hit. It's described pretty well in the article.
It was originally developed to be used with IIS which handles all of that.
IIS is not coming to Mac or Linux ( is a good thing !) - so you can/ will rely on Apache or NGINX to “front” your code just like you would for Ruby or Python or Node.