Who does source address validation? (was Re: what's that smell?)

So why doesn't c.root-servers.net provider or its peers implement this
"simple" solution? Its not a rhetorical question. If it was so simple,
I assume they would have done it already. PSI wrote one of the original
peering agreements that almost everyone else copied. If it was a
concern, I imagine PSI could have included the requirement, most of
their peers would have signed it 10 years ago. But they didn't.

My guess would be inertia. It tends to take quite some time to get
people off their butts to do something.

It is also a feature which protects others more than it protects you,
and there are serious psychological hurdles many providers (cf peering)
have to doing anything which might benefit someone else more than
it benefits them, even if it will benefit everyone over the long term.

Was uRPF even available 10 years ago?