Anyone can do it, it really comes down to what percentage of your income you can save, but it'll be easier for people with less expenses.
Here's a calculator that's been posted on HN before to give you some numbers [0].
Also, it's worth noting that 'retiring' doesn't have to mean not working anymore. To me it means the ability to work on whatever I want without having to worry about income. I'd likely still work on side projects, contribute to open source projects, etc.
