It's not always a fire. Small issues or questions stack up if I need to wait 30 minutes for a reply.

The point still stands. If you feel you need immediate answers the moment you have a question, there's a larger issue.

When an employee's in a meeting and not at their desk, what do you do?

No it doesn't. You can't plan for every contingency.

If they're not at desk, I'll wait there.

The point isn't that the project will fail if I don't get my solution right now. The problem is that having you remote, on the whole, will make it fail.

> The problem is that having you remote, on the whole, will make it fail

That's a figment of your imagination.