@J12t well "retail business" is part of the "shopping mall" metaphor, AT protocol services don't technically need to be provided by a retail business, but due to the nature of the architecture Bluesky is built upon retail/commercial business will most likely be the service providers.

When you set up a mastodon/pixelfed/lemmy/peertube/etc. instance you are building an independently operated server...metaphorically a place like a home, or pub, or a park or whatever...that is owned and operated top to bottom by you (or your team)...you maintain the app, decide how to store the data, manage logins/accounts, do the moderation etc. A fedi server/instance is thus a natural place to establish a community.

The way Bluesky and future AT services are designed to work is that "servers don't matter". You can provide logins/identities as a service, content moderation as another service, host applications like a microblog or video sharing or whatever as a service etc...and people pick and choose those services...