What problem does this address?

I registered some Patterns in a block theme.
Some of these patterns use blocks registered by 3rd party plugins, including some from Block Plugins like Video Popup Block by WPZOOM or The Icon Block.

Not relevant to the issue, but I ensured to test with Block Plugins that can be validated here and with regular plugins:
https://wordpress.org/plugins/developers/block-plugin-validator/

The issue is that when the plugins needed for some blocks used in patterns are deactivated, then the patterns don't appear at all in the Pattern inserter.

This took me a long time to figure out why some patterns were shown and why some were missing, no matter how much debugging I did.

What is your proposed solution?

I think the Pattern inserter should show all registered patterns, regardless of whether they include blocks from plugins that are active or not. Probably a warning added to such patterns would make more sense than hiding them. This would help both users of those themes and their developers who are trying to debug what's wrong.

The block editor already includes the necessary interface for blocks added to the content by currently inactive plugins, so why not use it for such patterns as well? Especially when using blocks from single-block plugins that can be easily installed and activated directly from the editor.

Happy to help with more feedback or testing!