FIRE is not because you wish to not work, but so that you can still live a decent life if you want to work but cannot find employment. I have read many trying anecdotes lately of engineers who are very capable who cannot succeed against the current hiring gauntlets. What good is a desire to contribute and perform meaningful work if you can't make it through the hiring circus? That is what you're derisking against. The labor market can remain irrational longer than you can remain solvent.

Relevant recent thread: https://news.ycombinator.com/item?id=35514464