Earlier quoted context omitted.
Interestingly, in some ways this is a big selling point of AWS/Azure/Goog. The absolute scale they can handle is way up there. The downside of course, is that whilst their infrastructure can likely handle it, handling the bill associated with 'just scale up your service' could be worse than the attack itself.
If Azure and Google would like to gain a competitive advantage over AWS, then I would suggest this: Build out a suite of tools for fighting DDOS. Enable private consultants and companies to provide this as a service. Do this in such a way, that cloud customers save money and have to worry about less. Hell, let companies jump in structured as insurance companies! Also bring in cooperation with law enforcement and use…
If I am an AWS customer I expect AWS to handle/prevent DDoS, same way as they do with S3 to achieve 11 9's availability (the files are saved in multiple AZs in the same region - Glacier IIRC copy files on different regions to avoid data loss in case of physical disaster).
One of the reason for choosing AWS is because AMZ has deep pockets and has the means (financial and technical) to fight against large DDoS attacks, while a smaller provider might not have to do that. Putting clients in a position to have to buy that sort of protection doesn't sound very smart to me.