[iscrewyou]

We can simply start by asking what does “syncing files” include?

Watching files. Keeping backup of files. Keeping conflicts resolved. Watching Selective Sync files and folders. Watching Smart Sync files and folders. Notifications for synced files. Etc. etc.

There’s way more the client does than what I mention.

[PurpleRamen]

I don't think there is much code for conflict-resolving in dropbox. Usually in case of conflicts it renames one of the involved files and add a message about conflict and the date to the name and moves on.

[varenc]

Perhaps there's lots of code to minimize the number of times a real conflict occurs?

[thijsvandien]

I agree that syncing is far from trivial, but that doesn't change it's a single purpose.

[kiriakasis]

Not to build a straw man but by this logic also a browser is a single purpose application

[paulddraper]

A rocket ship is also "single purpose."