tl;dr; Hiring young people increase headcount faster because they are cheaper and less productive, and headcount is an important metric in SV that correlates st

tl;dr; Hiring young people increase headcount faster because they are cheaper and less productive, and headcount is an important metric in SV that correlates strongly with the ability to raise funding, and the ability to have a successful exit later on. ---- One unmentioned thing, which is weird until you've seen it first hand, is that it's easier to sell and finance a bigger startup, and by "bigger", I mean: higher headcount. Obviously, in general, older people are more experienced and cost more, and also do more. However, this is a net-negative because you have a (potentially much) lower headcount. Another poster commented on how he'd take proverbial three LISPers over 20 NOOBS. (I have no doubt he's telling the truth.) Quick test: If I tell you startup A has 8 developers, and start up B has 80 developers, which startup seems "more successful" to you? Which seems likely to have had more funding? More market share? Is more stable? Better managed? Which seems likely to have an exit (esp. acquisition) in the future? It's little comfort knowing that startup A has 8 LISPers coding circles around the 80 devs at startup B struggling to make Grunt work and keep MongoDB from crashing. Politically, startup B is a much bigger success—at least in SV today. Startup B is what SV optimizes for and funds, and that leads very naturally to hiring young people—all else being equal.