It's a fools errand to ever believe in job security. Even if you're absolutely right on your importance, management can always remain stupid longer than you can remain employed.
It truly feels like a farce. I've survived a few rounds of layoffs and I've seen both shitty engineers and our best engineers let go. I assume our good ones are too expensive? It seems like HR just does some spreadsheet magic to grab people without any regard for performance or title.