Whenever something is done cheaply and it looks like it's not a cost issue because it's only miniscule part of the total cost of the product, it's usually actually is a cost issue. The buyer of the final product might not mind spending a little extra to have that one thing done a little better, but for the supplier of the sub-sub-contractor whose entire profit comes from doing that one thing, the "miniscule" part becomes 100% of the cost.

Not only that, but this is only one of many things that could be done more expensively. What if you add better fire resistance, better insulation, more weather resistant paint, more carefully assembled parts, etc. it ends up becoming quite a lot more expensive. It's a bit like the difference between a Mercedes and a Toyota. They both seem to be basically the same, but the Mercedes has slightly more expensive parts scattered all through it like a few dollars spent on fluid dampers on the adjustable seat backs compared to no damping.