In Brazil or anywhere, can you buy a car with the default sound system ripped out and get a refund for it? What about without the default tires, seats or even the engine?
You can ask here for cars without sound system, air conditioner, airbag, electric windows....
Never saw a lawsuit on that though, maybe because I never saw a manufacturer be stubborn regarding that.
Windows, OTOH, is something that you pay for, but generally comes in an OEM license. This license is non-transferable in most cases.
Why is the residual value so small? Lack of standardization. A lot of automakers use their own mounting system for the head unit, which means if I bought a Lexus and asked the dealer to take out the head unit, the dealer wouldn't be able to turn around and sell it to somebody who wanted a better unit in their Ford. It goes beyond the mounting system though.
A lot of automakers have their own plug and wiring standards too. If you buy an aftermarket head unit, you usually get a pigtail that plugs into it with unterminated wires on the other side. Then you buy a wiring harness kit specific to your car which has unterminated wires running into a plug that connects to the vehicle harness. Soldering ensues (or wire nuts or electrical tape for the lazy...). Since the aftermarket does have a strong incentive to standardize, the wires on the pigtail that come with the head unit match the colors of the wires in the harness kit, which actually make the process pretty straightforward if you're even halfway handy.
What all of that means is that the unit out of your hypothetical Lexus (which doesn't come with a pigtail with unterminated wires) is going to be hell to get working in somebody else's Ford. Between the physical and electrical incompatibility, the residual value of a head unit has to be pretty close to zero for anybody who doesn't own basically the same car.
It might fit if speeder was trying to buy a laptop without RAM or a hard drive so he could put in his own, but my reading of your comment is that you're talking about having a physical part of the product removed and wanting a refund. What speeder is asking for seems more like asking Lenovo to offer an option to order a car with an upgraded the sound system, tires, seats, or engine. This is something many auto makers offer.
It seems that Lenovo, in this case, has decided that the market for cars with steel wheels is too small, and is selling cars without that option. You can only get alloy wheels on your Lenovo car.