For those who are that having that being born on a family which does have that good financial status on which you would really be having a good start up just in case you would really be having plans on starting up some investment or business even into your early years on getting independent. Actually majority that those who would really be struggling is into those people who had entered the marriage life at early age on which they havent been able to prepared themselves and thats why on the moment that they have decided on starting up some business or investment, then they cant be able to do so not unless if they are on managerial or higher position then they could be having the budget, but what if not? You would really be just that living to pay up on daily expenses and with your debts and thats why not all people will really be that easily be trying out to get along with this FIRE plan.
As someone who wasn't born to some wealthy family (we were okay though, we weren't welfare level, my father worked and earned enough to survive thankfully) and got married very young, I can testify for this. It's very hard because first of all, you are not from a wealthy family so you are not given anything, my parents never gave me any money for me to survive, secondly when the time comes and you marry right away? That means you never had any time in between, so you never saved.
So you are now paying for your college still, you are paying for maybe the wedding and marriage and the house, rent or maybe mortgage don't know what level you are on, and building that house, and that takes years too. After that maybe a kid? Then you pay for everything for the kid. Suddenly, you are in your late 30's and you never saved an ounce, maybe even in debt, because you never got ready. I am not saying this has to be your future, but there are a lot of us like that.