"List" is just where I draw my line in the sand. Likewise the level I describe as where I think it becomes unethical.
I know manufacturers spend a lot of effort to determine what the maximum price a reasonable person will pay for an item is, taking into account their costs and expected mark-ups at each level of sale.
It's true that some manufacturers sell above list every day, but not to me. I knw they can and do get the prices they ask, but at the price of alienating their customers. Some companies have built successful businesses on this model, but I try to avoid those companies.
The companies I prefer to deal with may occasionally charge higher than list, but if they do, they will bring some other, maybe less tangible, value to the transaction.