> They have silo'd themselves into whatever niche project or have been on maintenance mode on a piece of software for years and never evolve. Sometimes it's not

> They have silo'd themselves into whatever niche project or have been on maintenance mode on a piece of software for years and never evolve. Sometimes it's not their fault, their company has pigeon-holed them into whatever software and they can't escape for whatever reason. I think your hypothesis is correct. In my experience, most of the devs I've seen in that position do it to themselves. They get comfortable in their part of the codebase and rarely venture outside. Instead of helping other devs ramp up in their codebase, they just close all the tickets out themselves since that's easier than actually getting someone up to speed. I've gotten close to that situation, but realized what was happening and worked with my manager to take on different projects. It definitely creeps up on you.