Yes, of course bandwidth is a concern, but then again there should be our way to monetize, and that's entirely possible using direct payments which already exist.
A little bit of cashing, CDN, and your phone as the initial file server. Tag a photo or video has shared.
Really it's just an RSS feed and CDN.
1. Bluesky allows you to use a domain as a handle by creating a TXT record on an _atproto subdomain of the domain you wish to use (see https://mxtoolbox.com/SuperTool.aspx?action=txt%3a_atproto.s... for mine)
2. You can also serve up your DID by having the URL "https://<handle>/xprc/com.atproto.identity.resolveHandle" return the DID.
3. AWS buckets have the URL structure http://s3.amazonaws.com/[bucket_name]/
4. register "xrpc" as an S3 bucket, drop a file named "com.atproto.identity.resolveHandle" with the correct JSON in it
5. boom! your username can now be s3.amazonaws.com
Hope that helps.
At a previous company I worked at, every bucket had the company name prefixed. Never had a problem with squatters.
I wonder if Amazon actually has any policies to prevent squatting.