[NalNezumi]

I'd like to think it is due bad HR practice, based on complaints about companies I've heard from recruiters.

The industry is still relatively young and the difference from one senior to another senior engineer is simply too wide to assess their competence with bad HR practices.

A senior engineer co-worker I had at previous big tech company had only experience working in big companies, and refused to learn new-tech. He stuck around his own module written in his own way, and rarely tried new platform/languages the department now used. Most HR people are told to avoid hiring a person like this, and with bad practices they just filter with age. That is at least the situation in Scandinavia.

This, while the industry cries for "tech talent shortages" and simultaneously refuse to hire entry-level engineers. The crazy thing is "old" in this context applies from 40+, according to a study conducted in my home country.