I guess the idea is that if you set up a team for something greenfieldish you want some to lead by example in terms of how the stack will be used. You don't wan

I guess the idea is that if you set up a team for something greenfieldish you want some to lead by example in terms of how the stack will be used. You don't want someone generally experienced to go deep discovering their way to use the stack, you want to buy usage patterns. Once the position is out of the trenches, it's not really a tech job anymore and you basically need someone who knows the language (of the field, not a programming language!) and who is good at not running into process traps. From the buyer side it makes a lot of sense, the problem is that when you're on the selling side and too old to get accepted in a junior role, you either have the precisely fitting CV (and can prove it through the interview stages), or you're bound for a tech stack consisting of an uber-accepted car.