For some, it is possible, but many people are unable or unwilling to retire early due to the fact that their monthly expenses outweigh their prospective non-working income, forcing them to work to meet the costs. Yet, whether or not to retire early is a personal decision.
It all comes back to yourself to prepare for early retirement or continue working to prepare for a much more adequate old age and I see that the decision to retire early or not is not only a matter of money but also desires and of course if someone wants to retire early they can when they have have a business or a steady income that continues even though he doesn't work anymore, but the amount won't be too big so he won't be able to fulfill many desires. I think that's the reason many people don't retire early.