I've always found this frustrating myself. I was never a fan of immaturity, but I have absolutely no patience for it at my age (it's one reason I hated my last

I've always found this frustrating myself. I was never a fan of immaturity, but I have absolutely no patience for it at my age (it's one reason I hated my last company). The cultish character of some startups and tech companies also creeps me out. In general, I guess an infantile workforce is easier to manipulate than a group of mature adults. Or maybe there's something in the free snacks... My personal experience has been that companies that need tech (vs. tech companies), as well as the older players, tend to have employees with a greater level of average or at least apparent average maturity. The Peter Pan syndrome you have in mind seems to be fairly unique to new tech, but not new businesses in general. Maybe instead of working for a tech company, you should consider working for a company that has a tech team instead.