A ~1 hour response time from identifying to mitigating the DDoS isn't exactly bad. I'd say their engineers did a pretty good job.
Security really isn't my strong suit, but isn't it standard practice to automate DDoS mitigation strategies?
Depends on the type and size of the DDoS and where on the network path it's hitting.
That doesn't really hold when their competitors have teams of engineers working on DDoS mitigations and successfully handle most of these attacks. Falling to a DoS is a technical failure just like other causes of outages.