Scalability is relatively new hiccup; given the fact that only in past few years users have swarmed the internet. Sites never expected that and developers weren't prepared. They learned mostly by trail and error and reading case studies and then figured out what to do. You would find inexperienced PHP devs who don't know scaling just like you would find .Net devs.

I think the article has the right notions. Stack doesn't matter, a team of highly motivated devs who can milk the technology involved is more important.