[wyqydsyq]

> All employer / employee relationships have this dynamic

Wrong, no employer relies on a newly hired employee the way they rely on a senior knowledge silo'd engineer with a decade+ of domain knowledge which they are reluctant to share. In most jobs the employee is not in a position to have that kind of bargaining leverage. That leverage is only gained by an employee either intentionally and maliciously making the codebase as esoteric and unmaintainable as possible, or poor management not planning for these risks sufficiently e.g. not hiring more staff for a legacy COBOL system team as it's members leave until there's only one guy left who understands it.

> While I think blackmail isn't an accurate description of this

I'd argue it is. You know their business depends on you as a result of you actively working to make it depend on you, you use that knowledge to leverage your position in bargaining for higher pay or to never get fired from a low-effort "cruiser" job. Essentially blackmailing the business into continuing your employment under threat of losses caused by you leaving and nobody else being able to maintain the mess you created. This is not a normal employer / employee relationship dynamic at all.