there are /some/ intricacies to DDoS, it's not all just "build a botnet and send packets". DNS amplification[1] is a good example of a non-straightforward augment, and there are all sorts of funny ideas people have that make it difficult to mitigate a dedicated attacker. the issue is that it's mostly (s)kids renting out botnets and spamming video game servers with layer3 packets.

[1] https://www.cloudflare.com/learning/ddos/dns-amplification-d...