See, the problem is that the people who care about cost performance and the people who care about UX performance are rarely the same people, and often neither side is empowered with the data or experience they need to bridge the gap.
Global public cloud spend is hundreds of billions of dollars a year. I wouldn't be surprised if it's AWS's marketing team that came up with the talking point about how much more expensive developer time is.
Edit: put this another way- wherever you work, you might know what parts of the architecture need some performance work but do you know what parts of the architecture cost the most money?
I might say, "hardware" is expensive compared to (my) salary :)
It doesn’t take engineering knowledge to browse through CloudWatch metrics and see that your average CPU utilization is in the single digits.