Do you know how AWS works? If so you probably know not every piece of AWS infrastructure will scale on the fly. Things such as databases (RDS) won't scale based on traffic. If those transaction servers are running on RDS, then this is probably what failed.
If its about server (EC2) instances, they probably hit some maximum limit they have setup. AWS doesn't let you scale indefinitely, as this would probably make you bankrupt before an attack was over. And this was basically a DDOS attack.
Too many transactions at once (the jumps) and after that fell over it became a DDOS on the login system. I honestly don't think they could have done much about this, there are always limits somewhere you can hit somehow even with the best planning.
Respect to the people fixing this on the weekend.
Reasonably well, although I am more of an Azure guy.
However, whilst I appreciate your comments, it's not me that made claims about using AWS to scale like this, It's Amazon and FDev themselves. Amazon even use Frontier as a case study;
https://aws.amazon.com/solutions/case-studies/frontier-games/ and they say "By using AWS, Frontier Games can scale compute resources easily
to handle large spikes in user traffic"
Here's the presentation;
https://www.slideshare.net/AmazonWe...realtime-commodities-market-aws-reinvent-2015 - Have a look at Slide 18. They make bold claims about the autoscaling infrastructure - using elasticache and auto scaling groups in front of the RDS you mention. Notably, they still refer to this environment as "massively multiplayer".
You mentioned on another post about the rate of change being the thing - and that's why I am annoyed. I have been involved in the architecture of two major systems that are massively scalable - one which had to cope with a massive influx (150k+ users) all at pretty much exactly 8.30am, and one which responded to the "stick the kettle on" ad break in major soaps.
In both cases, the admin team pre-warmed FE instances to cope with demand rather than letting the auto-scaling work completely on it's own. This event was well communicated ahead of time. FDev knew pretty much exactly within a few seconds when the spike was coming.
This should not have happened - and given the coverage of the event in the gaming press (hell, there has even been coverage in the non-gaming press), this absolutely should not have happened.