>>512899071 (OP)
The ridiculousness is an argument in favor.
Here's the thing. There are many ways to survive, and all of them are being tried. This leads to some pretty fucked up designs. All that has to be true is that a solution worked better than others in the same species and within a short period of time, the successful ones are those who eat regularly and most importantly pass on their winning genome.
We live on a planet that is inundated with radiation. The magnetic field protects from the harshest of this radiation, but subatomic particles are playing havoc with the genomes of everything all the time. Mutation is king. And rarely (like, super fucking rarely) a mutation is so innovative and solves so many problems that it becomes dominant in short order.
Our own brain size compared with chimpanzee cousins is a direct result of two chromosomes that are fucking damaged. The damage reduced the muscle that raises our lower jaw compared with the chimp and especially gorillas. If their teeth could survive it, they could crush ball bearings. Their muscles wrap around the top of the skull, it's so massive it's like our thigh muscle. This makes their skulls smaller volume. Our weaker jaw muscle led to larger brain size.
https://www.youtube.com/watch?v=9Tpqc6SVUWk&t=42