I really don't like how you characterize younger people able to work longer hours as something to do with motivation or drive. That's not the deciding factor, a

I really don't like how you characterize younger people able to work longer hours as something to do with motivation or drive. That's not the deciding factor, as many founders, including technical ones, of startups are well into their 30s. The reason older people can't work as long hours is simply because they often have families and other responsibilities when compared to someone in their early 20s. I also disagree that they're less costly due to their age. It's due to the lack of experience that commands a higher salary. I also think creativity is not related to age, again because many startup founders are 30s or older. As far as company culture, do you mean outings? You don't have to have a family to not want to participate in outings. Also for 'bonding': why do you think many younger professionals can have mentors well older than them? The only thing I could think of that might be a factor is that as you age, it is somewhat more difficult to learn new things as your brain is less malleable, so you may be slightly slower at picking up something completely new if you're 40 compared to 20. I would argue this isn't a factor though because most programming languages and systems are pretty similar, especially at startups.