[jek0]

A manager gave him the "senior" title. Where I am, "senior" means "experienced". When you need a senior developer in a team, means you need someone that went through many projects and know the errors and mistakes a team can make.

Building mental models is great, but you need to have used a few times in different context, to really appreciate when and how they were the most appropriate.

The experience of handling multi-years projects (and getting back to them after a few years too) has no equivalent.

You can read as much as you like, nothing beats experience, which you will get after years and years in the job.