If you replace the word "LLM" in your reply with "web browser", I think you'll see that the situation we're in with MCP servers isn't truly novel.

There are lots of tools to handle the many, many programs that execute untrusted code, contact untrusted servers, etc., and they will be deployed more and more as people get more serious about agents.

There are already a few fledgling "MCP security in a box" projects getting started out there. There will be more.