Files used to materialize without internet since beginning, it's not magical. We just needed the software installer file copied to hard drive.
I get that you have opinions, but you seem to have entirely missed that the runtime is downloaded at build time and included in the bundle. And god forbid if you like doing everything by hand, you don't have to use Nuget and you can manage every last dep by hand, however you like (and you'll likely end up hacking something that is less usable than just setting up a private nuget server, but "opinions").