> BCP38 is designed to filter such spoofed traffic, so that it never even traverses the network of an ISP that’s adopted the anti-spoofing measures. However, there are non-trivial economic reasons that many ISPs fail to adopt this best practice.

So, it costs too much to run clean internet pipes.

As the internet is a major part of the economy, as well as access to government (as well as government access to surveillance), it's probably time to regulate ISPs and related players for healthy operation, like water utilities.