I don't anyone is saying that. We are in a trouble shooting mode and dependent on what you tell us. If it is not the e-brake cables, then it could be the cylinder, or a bad/weak return spring, or a bad backing plate hanging the shoes, or something else. All we are sure of is that it is broke.
One thing to think about, when you replace the shoes, you push the wheel cylinder pistons back into their bores. Dirty brake fluid will/may have water in it that rusts the cylinder bore. When you push the pistons back you can break some of that crud loose. That rust/crud can cause the pistons in the cylinder to stick and not allow the shoe to return when you use old cylinders with new shoes. However, what usually happens is that the rust cuts the cylinder seals and the cylinder leaks. But, it has also been known to cause the cylinder to stick. That is the main reason that most folks replace or rebuild the cylinder when they replace the shoes.
Another thing, brake shoes can wear the backing plate and leave a ridge on it. If there is a ridge on the backing plate and you don't remove it, the new shoe can hang up on that ridge and fail to completely return.
We are just trying to give you ideas and ways you can check it out.