You roll Survival to survive, right? So a use of Survival might be "You're trapped in the Nevernever until the next full moon. Roll Survival, difficulty 7, take consequences to cover your margin of failure."
Knowledge skills are not weak, they just aren't significantly stronger than other skills. So splitting them would make them weak.
I see little relation between Athletics and Might and Weapons, honestly. Weightlifters don't run well, and swordsmen aren't generally great wrestlers.
But an excellent mathematician can generally handle computer science or biology. I've known a fair number of smart people, and only one or two were specialized. People rarely excel in only one subject at school.
See, that's my point. In your version of Survival, you're not only abstracting away what survival actually entails, you're simply handwaving it out of existence. I, meanwhile, would be running a stranded in the Nevernever as a significant event, possibly worth a milestone all by itself, complete with Stealth to avoid detection by predators, Craftsmanship to create shelter if you couldn't find something with your Investigation rolls, which would also be used with Lore as a limiter to find food to keep yourself fed through the night, and then likely throw in a Thaumaturgy Challenge to get the gate open at the proper window of time to get back out before the big nasty you were hiding from clues in to the scent of magic being used. A single skill for all of that just wouldn't cut it for me.
On the other hand, a person with Might is more likely to have a higher Weapons or Fight skill than someone who has nothing. A person with Weapons will almost certainly have both Might and Athletics at a fair level, since cardio and strength training are both explicit parts of combat training (note that I am talking about COMBAT training, not simply martial arts classes at a community college in a vaccuum of intent. A recreational T'ai Chi practitioner MIGHT justify having a low Fists with little to no corresponding physical skills, but that'd be a stretch.) Again, they're definitely distinct, and yet they will have a tendency to be linked.
As for smart people knowing a lot, yes, I mentioned that tendency, but I don't think that's because they simply have a high knowledge skill, especially before you get to graduate studies (which is the bare minimum I'd consider before you got to Good skill, btw), I view that as them actually investing in knowledge skills in a balanced way. Most smart people I know I wouldn't put above Average or Fair skill. Getting Good or higher takes some real work, which talent alone simply can not match. I don't think it's unusual enough for someone to know more about programming than biology to make it worthy of a Stunt. Hence the skill split.
