Could a man buy a big box store apple tree that isn’t disassociate resistant and graft say a blight resistant apple varieties to it and the tree become resistant or would I need to cut all the way off and cleft and bark graft to achieve this
It's a crap shoot.
Lot's of studies have shown that the rootstock has a great deal to do with disease resistance, and when you buy a box store tree you have no idea what the rootstock is. You could be buying something that does well or ends up a horrible failure. I guess it depends on how much of a pioneer you are, how much extra time you have, how much extra money you have, and how much extra space you have.
You could even end up with an M7, which has been described by some experts as a "noxious weed." A high percentage of them will just eventually fall over without some type of support. And M7 has been popular with a lot of commercial growers, because they do support them and don't care, so a lot of the rootstock is available. That makes it more likely for you to get it, because they are going to use the cheapest thing available in the box store trees.
If you want to learn more about how rootstock affect the disease resistance and other factors at the molecular level, you can read the following thread: http://deerhunterforum.com/index.php?threads/the-forbidden-apple-tree-knowledge-thread.2478/
My advice is to start out with a good proven rootstock that fits your soils and meets you other growing needs. When you can, choose from B118, M111 or Antonovka whenever possible, and use caution when you choose something else.
There is also a theory that you can set the graft extra deep and the tree will root above the graft and make a full sized tree on its own roots. I'm trying that on a few trees right now but it is going to take a few years to see if it works. I need to see for myself, because I've learned you can trust a bunch of apple hippies to give good information.
Even when you do everything right you still have a slight risk of some type of graft incompatibility between rootstock and scion that hasn't been publicized by anyone yet, but that risk is a lot lower than starting out with a box store tree.
Best wishes and good luck.