Sometimes you think you're not "working" but you are thinking about your work. So you "work" 2h/day by really typing and coding and so on, but you think about some problem another 2 or 3h/day. So you have to consider that, too.
In my decade+ experience of work, on executive as well as producer levels, I've found that most people that produce this argument are not very productive when it comes to delivering actual business value.
The situations I am aware of are very far away from needing to spend 100% or 200% of their actual working hours in thought for the implementation and / or strategizing.
I haven't worked in deep tech, or cutting edge, so it might be attributed to this.
