> Once you get 3gbit traffic on your 1gbit link, you can't do anything yourself - the only thing that can save you is a bigger pipe.

Realistically, out of the DDoS we typically see, how many are in fact "they had bigger pipes than you"? I've come across that once in my ~3 decade career maintaining infrastructure for websites, some quite popular. Most of the time the attacks are relatively low-effort and easy to stave away, there been one time when the attacker seemed to have basically endless amount of resources, and yes, that time we ended up with emergency calls to Akamai.

But again, those sort of attacks seem to happen seldom, and I don't think people should default to trying to prevent them. Deal with that once you get there, because most websites and services never get there in the first.