An 800 pound gorilla (DHL) tried to use SAP for digital transformation, and lost $1 Billion in the process. When in IMO they could have achieved all this under $10-$20 Million, only if they had hired 50-100 full stack Rails developers.
But neither do they know what is a full stack developer nor Rails. They just know SAP and Oracle. That their teachers taught them in the 90s. On a serious note, scaling is the major issue for a company of that size, But I guess Rails could have handled it easily. For instance most probably twitter runs on Rails too.