In the general human mindset, there's a huge difference between "they're adding extra for those who pay more" and "they're taking stuff away from those who pay less".
If the feature differentiation is achieved by taking the premium offering and adding a component to remove functionality, then that feels a lot worse than taking the mid-range offering and adding components to result in the premium one.
In this case it does cost less to produce since they don't have to develop a new product and setup separate manufacturing processes. That piece of foam saves a lot of money.
Software doesn't have a per-unit manufacturing cost, and everyone knows that, so it does feel bad if a firm offers different versions of the software based on price.
Hardware does have a per-unit manufacturing cost, and people expect a more expensive product to cost more to make.
If the feature differentiation is achieved by taking the premium offering and adding a component to remove functionality, then that feels a lot worse than taking the mid-range offering and adding components to result in the premium one.