For example, why would one write a kanban plugin when you can stream data to a dedicated kanban app like Trello? Or a calendar plugin when there are Google Calendars? Some plugins require a view pane and aren’t able to have codeblock. But with websites you can always embed them with iframe tag.
Following this logic, would there be a plugin for social network, video conferencing, because people don’t like Facebook or Zoom? I know that this would make the Obsidian ecosystem richer, but why would people have to do that?
For me: staying in Obsidian and staying text-based Markdown is key. Fewer context switches. And all of the many other reasons Obsidian does what it does, differently, for any individual user out there.