The article argues that lines-of-code is bad metric, and no one argues about this.
thuanao proposes measuring "number of completed projects", and I think it's a pretty good metric in some situations which don't involve long-term maintenance.
One example I can come up with is data science: two engineers are given identical requirements to ingest the data (once) and calculate certain metrics. If the assignments are identical, we can calculate and compare their productivity, in "projects/month"