I'm half with you, and I see both sides.
When it's done well, I think it's a fantastic approach. I'm in a situation right now where I'm kind of that "expert". Not because it was planned that way, but because I was the only person on the project at the start. Now I've got a couple of young EEs working under me, and they do most of the development work while I sit in meetings for a good chunk of the day. I come in and help with the hard problems, but most of the day-to-day work is on them. It's working out great because it seems I got the structure relatively right (they've changed things a little bit as they've added new things I didn't think of, and I've reviewed and supported those changes)
The flip side is ${JOB-2} for me. It was a similar situation; an "expert" laid the foundations and then got pulled off to do other projects. There were two main differences between my current situation and that one:
- The infrastructure he put together was not great and full of footguns (e.g. accidentally implicitly double-encoding HTTP requests, bizarre cookie handling, etc)
- The code was hard to change because of how it was integrated, and the team didn't feel particularly empowered to fix it
- He was barely around (being assigned to something in a different building).
- He pushed back hard when people suggested that there might be problems with it and fixes required. Instead of facilitating and reviewing, he'd pop by occasionally, look at things that changed in his absence, and shit on them.
As I'm writing this, I'm reflecting on whether or not I'm contributing enough to the long-term development of this codebase, and I'm feeling relatively ok with the answer. Ultimately, this product is still my baby and whether or not it's successful is on me. Maybe that's the difference? I'm quite invested in the foundations I laid, and more than happy to help my team work through issues they find in it?