What's the difference between early retirement and working till you're 65? You can't forecast cost increases as an employee either.
There's no guarantee your salary will keep up with inflation. If you get fired or retrenched, your earnings will go South while costs go up which would put you in an even more precarious position financially.
My formula is simple. In Singapore, financial independence should be around the $5 million figure.
At 4% return after taxes, this should give you a comfortable $200,000 per annum income without having to touch your principal sum. If you can save some of the returns and compound the interest, you'll be very secure.
Should anything untoward happen along the way, simply dip into your principal to make up the difference and return the amount in subsequent years in order to maintain that figure of $5 million in productive assets.
As you can see, achieving financial independence and retiring early offers you far more financial security than living from hand to mouth as an employee where you have no control whatsoever over your destiny.