This is comparing totally different numbers than what is being compared in the OP. I'm not exactly sure what Gartner includes in its "IaaS" revenue figures, no

This is comparing totally different numbers than what is being compared in the OP. I'm not exactly sure what Gartner includes in its "IaaS" revenue figures, nor am I sure what Forbes is including in its "cloud" revenue figures, but even Amazon's official press release [1] (which is what the OP is comparing) gives completely different numbers for 2017 AWS revenues than Gartner. 1: https://ir.aboutamazon.com/news-releases/news-release-details/amazoncom-announces-third-quarter-sales-29-566-billion https://ir.aboutamazon.com/news-releases/news-release-detail...