It depends on several factors like country, sector, and who you work. But as you grow older you are forced to either become a manager or sales person. I guess

It depends on several factors like country, sector, and who you work. But as you grow older you are forced to either become a manager or sales person. I guess the question is not about age, but wages. In your 20s you still don't know how much money you'll need for a living. When you realize how much you need, you buy a house/car/whatever else expensive enought not to be paid upfront, then unexpectedly have family, then kids and you know you need money. Much more than you get from a technical position. BTW, remember for the business you are an expense, something they need to build the product, but eventually all technical stuff can be bought or outsourced.