Even if I think the same, for you the rest of the day is really "lost" meaning you'd rather work on/do the stuff you were doing between 4:30 - 8 AM all day?
Yes and no ... Being an introvert I need a certain number of hours alone for "projects" :)
I'm responsible for my young kids and my ageing parents need more support as well and those are things I don't want to not do, they just take up time. And unfortunately the relationship with my partner probably doesn't get the attention it deserves either. Luckily she's KO until 8AM anyway.
I do also love being outdoors going for run / hike / mtb ride or spending meaningful time with my kids, weather / seasons permitting. They're still a bit young so I'm looking forward to the future wrt to that.