Yeah, this seems like one of those "correlation is not causation" situations. If you noticed that languages many people loved were correlated to languages that were used for new projects, it seems crazy to eliminate "loved language causes people choose it for new projects" in favor of "people choose it for new projects causes loved language".
The article makes the observation that "loved languages don't have legacy codebases". Also, using Ruby as an example, it postulates that "once a language has enough legacy codebases, it stops being a loved language".
I suspect there are two C#s in play here - the original C# in which many legacy/enterprise-y codebases are written, and the C# on .NET Core which is a fairly new ecosystem.
