No, there is nothing about you or your skills that is so unique that you cannot be replaced.
And if your severance package depends upon you teaching your replacement how to do your job (see Disney), you are even easier to replace.
I have skills that are useful and hard to find.
They may be useful, but they are not hard to find.
And yeah, I get that sucks. But the solution is to learn more skills so you can get the first type of job.
Unless you personally are working for Google or Facebook that kind of invalidates your position. You aren't so rare that Google is fighting to get you.
Look up "confirmation bias". You think that because your decisions have resulted in your position that anyone who has not achieved that position has made incorrect decisions. The reality is that when a company wants to cut their IT costs to save money, your skills will have nothing to do with their decision.