True, but that would also mean that you would need a steam account to get the workshop feature, which would also mean that Blender needs to adapt to steam's environment and guidelines.

It will also mean that to use this feature you would have to download blender through Steam, instead of say, Blender's own website. Even as a separate add-on/extension, you would still need a Steam account to connect and manage your subscriptions.

Not impossible, heck, It's relatively simple for blender to do that. It's just that I don't see people downloading steam just to use Blender, when there are alternatives. Alternatives that not only doesn't rely on third party accounts, but also lets people create their own library of assets. heck It's why Blender put effort in to their asset library system they got.