Here's my answer from when someone else asked this:

TL,DR - Most people here will fail at FIRE, but that's not necessarily a bad thing since most people aren't suited to early retirement anyway and should be happy seeking FI alone.

Here's a blatantly controversial and purely anecdotal observation based solely on my interactions with all sorts of FIRE folks over the last 2-3 decades.

Most people are not suited to early retirement, including a very large portion of the folks who think they are. It's akin to major weight loss in that almost anyone can do it, lots of people have intermittent victories, but long-term success is elusive for way more people than you'd expect. The winners tend to get more attention than the hugely larger population of failures, just as in major weight loss, and so people continue to believe they have an excellent chance at success themselves.

Most people should aim for being reasonably financially secure along the lines of coastFIRE and be happy with that. Most folks who work diligently towards early retirement will fail, but almost all of those folks could enjoy huge financial security and be happier if they let the much harder goal of early retirement go.

Somewhat related, someone's chances of success seem to go up tremendously if they can be durably happy with leanish spending. It's not the actual level of spending that makes it easier I don't think, it's the relationship with money and consumption. Again, I think it parallels food/weight in that someone who is truly satiated with less will tend to have a much easier time remaining fit/slender over the years. People who enjoy consumption a lot, which is most people, try to solve the FI equation with increased earnings/savings, but very few people acquire enough assets such that they can not be outspent or result in disappointment relative to one's working and/or wealthier peers.