Tangential to this point, but I've seen firsthand in a limited capacity but also heard of this from other devs, but there seem to be a decent number of devs who go from job to job doing the same thing over and over again. An example I've seen: a junior dev learns Springboot at a job, then goes from job to job converting their microservices to Springboot. When that project is complete (can take 1 to 2 years in some cases), they get bored or change jobs for a bump in pay and do the same thing again. As they do this a few times, they become a specialist in that field and they start self-selecting to only doing that one thing over and over and over again.

Is this widespread? Anyone else noticed this phenomenon?