Can't he comb his damn hair?

He acknowledges that in one of his videos, actually (he has a caption at the end with some throwaway joke about copying Tim Burton's hair) so I guess it's at least kind of deliberate.

Yeah, he mentions his hair in a number of videos, and examines the issue more closely in at least one of his videos, "Fear Not the Cutting of Hair".

For one, evolution isn't about "efficiency." If being more efficient at something gives an organism an advantage, it'll be selected for, but if you need (for the sake of argument) five fish to grow up and reproduce, and fish are abundant, being more efficient at getting your five fish won't give you any advantage in reproduction. You also won't keep getting generations of more efficient sharks just because. If fish stocks declined, then sure, being more energy efficient would likely mean you'd be more likely to reproduce and pass on that trait.

He's kinda-sorta right with the tail producing more thrust, but it's also to do with the musculature of the shark (which differs from most fish) and while lift is involved, shark livers often help with buoyancy.

Probably the biggest thing that bugs me about his "theory" is that efficiency is the centerpiece of his thesis. If sharks were really efficient, most of them wouldn't need to keep moving (using energy) to maintain water flow over their gills.

I think the problem is that he's looking at evolution like an engineer/historian. He's got an end product that he wants to nail a story onto, like the development of a given weapon or building technique, and that's not how evolution works.