It's not rocket science. Younger devs can be paid less and generally will voluntarily work longer hours for free.
Sure, you need some senior developers mixed in as well but young energetic devs are more bang for the buck.
Sure, you need some senior developers mixed in as well but young energetic devs are more bang for the buck.
From a "getting things done" perspective, I would vehemently disagree with you. If you care about things like 'having more reports' and 'spending investor money', then yes, you're correct.
The correct definition for senior developer vs junior developer is 'delivers company value without handholding' (vs 'with handholding'). If you've lucked into a young, hardworking dev who can do the former, remember to pay them well and don't burn them out. That crop will produce year after year for a while instead of just once or twice.
What I have seen is that when the younger ones look like they're working really hard, it's usually because they don't have a full grasp on whatever the task is, and they're putting in more hours because they keep getting their work wrong.
TBH I've only ever seen this from middle-aged company men.