Obviously, I don't like up-paying for features I don't get to use. The price of the product must be the same, having benefited from mass production. With that being the case, I'm actually glad I have the option to save money now and upgrade later.

The concept isn't a problem, it's companies taking advantage of it (and us).

To borrow a phrase you used earlier, I truly don't believe that we need to come to terms with companies blurring this line and taking advantage of us.

Which is a real thing that has actually happened.

The functionality exists, the code already has been written, but it's disabled so as to extract more money.

The arguments about cheaper manufacturing is pretty well pointless. If the cost of adding seat heaters is negligible, what justification is there for charging extra? You pay for the hardware either way. This is rent seeking and nothing more.

This is a topic that's been beaten to death in the electronics industry for years. Oscilloscope manufacturers design and sell a 500MHz scope, but cripple it to 200MHz unless you pay 50% more. Or they put 16MSample of memory in and restrict you to 8 unless you pay $400 for an "upgrade". The cost of buying the lower model and upgrading it later is usually much higher than just buying the high end model.

In any case, it's not like manufacturers are selling the lower tier model at a loss. They're taking lower margins on the crippled hardware, yes, but then they charge you ridiculous prices that are orders of magnitude above the real cost of the additional hardware.

Not true. The price you have decided you are willing to pay assumes it is not there. Your payment allocates no portion to the hardware. If you have decided a car is worth $30,000, that is what you are willing to pay, regardless of whether or not they include the hardware.

And, in actuality, you might even consider a car with said hardware to be worth less as it adds weight which will require more fuel and wear and tear expenses over the operating lifetime of the vehicle. The car worth $30,000 without heated seats is, perhaps, only worth $29,000 if the hardware is included.

The cost to manufacturer is their problem. Your value determination is entirely independent of that. Should it cost them $1 or $100,000 to build that $30,000 car – it doesn't matter. You are paying for the value you think you will derive from owing the car, not what it cost them to make it.

Indeed, in the long run the value has to exceed the cost of manufacture, else the business will soon find itself filing for bankruptcy. But in the short term, it is not uncommon to see input costs exceed the value of the product, resulting in a net loss for the business. The buyer doesn't care. Input costs mean absolutely nothing to them.