[wpietri]

Can you give an example of a company that failed because somebody chose Python? Or even one with materially worse business results, say a 20% reduction in revenue?

My guess is no, because people make fine businesses out of nominally unscalable technologies all the time. Rails is a notorious performance pig, for example, but there are plenty of successful businesses built in it. When server bottlenecks become an issue, modest performance tricks and ops magic are applied, and suddenly per-server performance is no longer the problem. And still, despite being a pig, Rails is a great place to start, because its real power is not CPU efficiency, but ease with which you can get something workable up and then iterate.

There is no language that is so fast that it's infinitely scalable out of the box. Every software company that grows hits performance problems with naive uses of the tools at hand. Every successful one figures out how to make things work. And making technologies serve the human purpose at hand isn't a characteristic of good languages; it's a characteristic of good teams.