And nobody is not expendable.
I'm glad you think that...could you do me a favor and come and take over my manager's position, and their manager, and their manager, etc?
No, in the real world everyone is expendable to a company. Sure it might be very hard for my company to find a new programmer of my caliber, but the reality is that eventually they would. It might take them up to a year to replace me, but they can still do it, and that makes me expendable.
There's an approximate 6,973,738,433 people in the world. If even 1/2% of them were programmers then that makes 34,868,692 programmers to potentially hire. If half of them are employed, that leaves 17,434,346 people. Now let's say that only a quarter of them are at or above my skill level, that means there are 4,358,586 people who could easily replace me in my job. Now, consider that up to 5% of the population is willing to relocate for my salary, then that means there are ultimately 217,929 people that could easily be brought in next week to take over my position. Point is, I'm expendable no matter how hard I try to make my self in-expendable.