> Turning yourself into a silo like this is practically blackmailing your employer into keeping you. They might keep you employed because they need to keep their systems online, but they will also not think twice about replacing you as soon as an opportunity is presented.
All employer / employee relationships have this dynamic. I get paid _n_ because my employer cannot figure out an effective way to do it cheaper, but as soon as they can I will no longer be paid _n_. While I think blackmail isn't an accurate description of this, what you're describing exists in all employment situations. Making yourself more disposable is only going to give the employer more power, which might work out better or worse depending on the employer.
All employer / employee relationships have this dynamic. I get paid _n_ because my employer cannot figure out an effective way to do it cheaper, but as soon as they can I will no longer be paid _n_. While I think blackmail isn't an accurate description of this, what you're describing exists in all employment situations. Making yourself more disposable is only going to give the employer more power, which might work out better or worse depending on the employer.