Too bad this was written as a Cloudflare advert, instead of emphasizing the changes that ISPs need to make (ingress source address verification) to make these attacks much harder.
I'd argue rather than this, we need to be able take Flowspec (RFC5575), and make it more reasonable for transit.
uRPF is a challenge. In some cases, the consequence is flows must route symmetrically through a given network. That's not always the most efficient, flexible, or cost-effective way to go, particularly if you're a large provider sloshing massive amounts of traffic through your network.
if edge networks implemented uRPF, it would put a huge dent in the ease of mounting DDoS attacks. unfortunately, the economics aren't there.
If uRPF was stopping me from successfully attacking a destination, I would just not spoof. ACLs, uRPF, and anything stateful are still not going to 100% mitigate an attack from a broad range of addresses.