Skills and memory are .md files on your system.

> The difference obviously being, his way you own the memories; in what's currently deployed, it's the platform that owns them.

I don't think you are very familiar with the state of LLM assistants. Prompt files were a thing since ever, and all mainstream coding assistants support storing your personal notes in your own files in multiple ways. Prompt files, instruction files, AGENTS.md, etc.