The costs associated with tablets also include the intangibles, like research and development budgets for both the device and many of the new specialized components. Netbooks were just a result of the race to the bottom in the notebook space, so not much R&D had to be spent to figure out how to make the cheapest (both in price and quality) systems. Tablets also are in the new patent minefield, so likely licensing costs are being passed on to the consumer currently.

As far as the horrible working conditions, it's definitely a shame to see, and is a result of the overall race to the bottom in the industry. Computing devices seem to be that rare exception where people expect newer more powerful devices for cheaper over time. Corners have to be cut somewhere if people expect tablets to be $200, a price point that modern smartphones also sit well above when you ignore the subsidy.