What I don't understand is why this isn't already the case. Every single EU(and UK!) airport I've ever been to has a fallback to agents sitting at nearby gates

What I don't understand is why this isn't already the case. Every single EU(and UK!) airport I've ever been to has a fallback to agents sitting at nearby gates if the eGate fails to recognize you for any reason. It just says "please proceed to agent" and you get back in the queue for families with kids and non-EU citizens etc. Why can't the same system work here?