On the issue of Magic:
If magic is so plentiful and not rare, Scow, then why do we even have warriors? Why doesn't everyone use Magic?
The Redguards never used one hint of eastern magic, yet they carved through the Goblins, Orcs, Elves, and Men of Volenfell, and kicked total ass without using magic. If you read every war related book, including the one on pale pass, most soldiers are regular foot soldiers or cavalry and not mages. Thus, it goes to show that mages are rare, and not just anyone can learn magic. More importantly, you have to pay to be instructed in it, like education in the modern world. Everyone has to pay for college, unless you have a scholarship. Unfortunately, there is no high school in TES. Therefore I make the assumption that if Magic was so plentiful, there would be no use for any kind of warriors.
Because magic isn't all-powerful as you seem to think it is. Redguards are awesome enough without eastern magic. According to lore, the Redguards are so skilled they blew up a continent using a
sword technique. We have yet to see a Mage replicate a similarly awesome act with Eastern Magic. Magic isn't necessary if a race is inherently bad-ass enough. Redguards are Stronger, Faster, More Agile, and Tougher than the average Nedic man. Does that answer your question? Also, Bretons have an inclination to not use magic despite their natural inclination toward it because it has a distressing tendency to outright
not work against them. On the other hand, Altmer are almost exclusively mages of some sort, because not only does it come easily to them, but it's also rewarding to use against them. Dunmer get a mix of magic users and mundane warriors because while they're capable of spellcasting, they don't have a natural inclination to it as the Bretons or Altmer, and the most spectacular Destructive Magic effect (Fire!) is... underwhelming, to a Dunmer.
Racial inclination toward magic and size of the available magicka pool makes it Not Worth The Effort for a lot of people as well. It's no easier to learn magic if you have a Magicka pool of 50 or 150, so races with the former has much less inclination to study magic when they've got a good enough sword arm. Why would a soldier want to waste years of training on creating fireballs when he lacks the ability to cast enough to kill his foes before they're close enough to stab him in the face?
Why use spell when you can do more with sword? And you just contradicted yoursefl, sort of. Magic is widely available, like college.
Most people can't afford it, but again, a 33% of a population being magic users is still an extreme minority. And the discussed numbers are 10-25%, which is still one out of every ten soldiers. So, in a group of 1,000 warriors, 100 are potentially dedicated battlemages, and an additional 150-250 assorted warriors augmented with spellcasting.