I’m assuming Gnome Web, Firefox, Chrome, Chromium, Brave, etc. will come to Flathub eventually. I guess web browsers are relatively difficult to package. But indeed for starters GNOME would do well to publish all of it’s (core) applications as Flatpaks on Flathub, and Web is one of few that’s still missing currently.
I feel like this argument went out the window with Flathub recently adding a lot more CI/CD features to its infrastructure. Seems like they have made it easier to automatically create and publish new builds. Not sure if they have a webhook yet for upstream CI/CD systems to trigger, but it surely can’t be unsuitable for Firefox by now.
This is not a blocking issue for Flathub. There are various Flatpaks published there that are wrappers around pre-built proprietary binaries. Like Visual Studio Code. It even comes with a nice statement in the description:
This is the proprietary Microsoft build of Visual Studio Code, packaged into a Flatpak. This repackaging is not supported by Microsoft.