The reason your tires wear are on the inside is because they are off camber like this. //====\\
There a a few reasons that makes your tires off camber like this.
Overloading. Or, the axel bend is gone from the axel. (it is supposed to have a bend up in the middle). Bent spindles on each end. (unlikely that both ends would be bent upward by the same amount.)
There are some things that are NOT likely responsible...
Tires....If tires were or are defective, or under-inflated they will wear on both edges pretty equally. not just on ONE inside or outside edge. I doubt it is faulty tires that are responsible for that wear pattern.
Bearings...Bad bearings will give you other problems. But not likely wear on one edge of the tires.
Best to get a real professional alignment done by a trailer or heavy equipment specialist. With laser equipment. That is the only real way to know exactly where the problem is, and what to best do about fixing it. Without this you are just guessing at the problem, and will probably spend a lot of money on useless repairs that don't repair the real problem.