I worked at a Canadian bank that operated like this. They had one "rock star" UI/UX developer that was deployed to build every new customer-facing initiative, but they moved them to the next project as soon as the current one made it to the testing phase.

The residual team was left to clean up their code and make it work, which often involved significant rework.

I raised my concerns with management that they were cheating their "rock star" dev out of valuable learning experiences and perpetuating the problem - the dev made the same errors on each new project. Not to mention, perpetuating their testing nightmares.