My impression is that coding requires more energy and enthusiasm (so, in other words, internal motivation) to do a good job than many other professions. Hence 5 year exp "senior" can do a better job than a jaded and complacent 15 year exp one.
I don't know about that. Surely expertise can make up for "energy and enthusiasm" (even after decades nobody knows everything about programming). It sounds a little like a post hoc justification of age discrimination.
In my impression, people who have been coding for 5 years already have plenty of experience, esp. if they are enthusiastic about learning. They may not be team lead material yet, but they should make a fine individual contributor.
