The FIRE lifestyle is all very Dave Ramsey, rice & beansy.
I consider my salary to be good but not awesome at €70k-ish a year. I put about 40% of my income away in pensions, savings/investments and mortgage overpayments. This will enable me to reduce my working year further and (if I really really want to) to retire (relatively) early at 55. So far for FIREy...
BUT we also go on holidays twice a year, go to concerts (babysitter required as well as tickets), eat out when we want, buy the food we like to cook at home, have health club membership and just generally have nice things. We don't particularly deny ourselves much of anything: we pay €56 a week to get cleaners in which is about un-FIREy as it gets. I'd say I spend another few grand a year on nice things on top of that.
It's really not at all necessary to go nuts with frugality to cut way back on your expenditure and line yourself for an early retirement. Just shopping around a bit and not being stupid will do most of the heavy lifting.
It's also important to remember that experiences make people happier than things. (That's not me saying it, there's actual serious research on the subject!) So even if you are splurging, you're really much better off dropping a grand on a holiday than on the latest iphone for example.
The first thing is why are people doing jobs that they hate so much that they want to get out of it as soon as they can? Do something else that you enjoy doing.
My perspective on that is why are people not working on having personal lives they want to retire to? The vast majority of people could literally die tomorrow and some of their colleagues might be shocked and sad for a week or two but that'd be it. I've seen it: lovely people dropped dead at relatively young ages and even the medium-term personal impact on their work colleagues was near zero. Their families were surely devastated but not their colleagues. Why give so much to work when work only gives you a paycheck in return?
Work to live.