I really like Rachel's blog and I think I understand the point she's making here. However I think she sees it from the point of view of very large scale service

I really like Rachel's blog and I think I understand the point she's making here. However I think she sees it from the point of view of very large scale services. In many cases you can have a solution ready more quickly with less developer time if you use these technologies, and at smaller scale this more than pays for the additional hardware you need to cope with the inefficiency. In such cases writing services in python is pragmatic and sensible.