I'm not 100% sure what the destination platform was that was only 20% the AWS cost. Digital Ocean? A "myriad of other SaaS platforms"? Self-hosted in a colo datacenter somewhere? How does this newer solution scale? What are the intangible costs, and are there additional staff considerations? Do you answer the pager at 2AM when a physical piece of hardware goes down?
Digital ocean doesn't charge traffic costs. I'm not sure if that was used in the article, but DO can provide significant savings for high-bandwidth services.