Software is generally a winner-take-all market. Software has zero marginal cost, so the company with the most revenue can invest the most upfront into making a

Software is generally a winner-take-all market. Software has zero marginal cost, so the company with the most revenue can invest the most upfront into making a better product, giving it even more revenue. Furthermore, in most cases there is little incentive for customers to ever use the second best product in a segment. So when building software, you not only have to meet the customers needs, you have to meet the customer needs better than any competitor. If you produce a product that is half as good or improve the product half as quickly, you do not lose just half your revenue, you could lose all of it. The second aspect of software development is that a developer working 40 hours a week is more productive than two developers working 20 hours a week. With the sole developer, there less communication overhead, less management overhead, and the ratio of productive time to time learning the system and understanding the interlocking parts is higher. This is the classic mythical man month problem. The third aspect of software development is that directly measuring output and effort of an engineer is very difficult. So as a proxy, managers look for signs of passion and engagement. If you are passionate and smart, but are slow to implement some feature, management will believe the feature was simply more difficult than anticipated. If you generally are not passionate about your work, and are slow to implement some feature, management will think you are slacking and fire you. Creating an effective company requires creating a culture of passion and hardwork, and having one person only work part-time can decrease the morale of those putting in 40+ hours. Asking to only work half-time betrays a lack of passion, and could be a bad career move. So the net result of these factors is that a company must work at maximum efficiency, and maximum efficiency comes when all developers are working 40+ hours a week. It is not in the company's interest to let you work only 20 hours a week, and it could indeed be risky if you bring the idea up with management. I should also note that the above dynamic is not just the case in software, but in virtually all high paying jobs, from professional athlete to corporate lawyer to corporate executive. Virtually all high paying jobs have some sort of competitive, winner take all dynamic in the market at large (the winners being the ones who get paid well), and within the company, the high paid people are the ones with specialized, hard to replace skills, that have a large ramp up time to learn effectively (learning a large code base, learning a set of legal traditions, learning how to hit a curveball, etc, etc). Thus in order to earn the high pay you must work long hours, and you must work many productive hours on top of a base of ramping-up hours.