There's "boring" and there's "content", and OP is probably talking about the latter. Once you have a family it takes over a lot of the energy you could previously use for work, and that's both expected and desirable.
The evidence is that a society filled with bitter, maladjusted people who's parents were too busy pouring their heart and soul into work to provide a stable, loving family household is one nobody should want. Like, there's shades of grey here, but you should prioritise your children over your next Jira ticket.
evidence required.