I could picture a CPU design that had a boot key or other restricted features set by blowing fuses (or similar tricks) during packaging. The "developer" unit leaves them unblown.
If they're selling 10M "regular" units per year, and 5000 "developer" models over the product lifetime, you have to amortize the cost of special-casing the production line for a short run, and stocking and supporting a second SKU, over a relatively small sales volume. It could well be more expensive than the few cents of electricity per unit to blow the fuses in a standard unit.
Already now, high-end general purpose computer parts can be more expensive than an embedded, restricted package. The embedded market can operate at a loss because their revenue is based on subscription services. The recent releases of new NVidia and AMD parts is a perfect example: AMD's share of TSMC's capacity was allocated mostly to produce the PS 5 and the Xbox Series X/S, while Samsung (NVidia's fab) clearly couldn't handle the sheer demand for the RTX 3000 series. Fortunately there are several OEM PC manufacturers still, but in the long term they will follow where the market forces blow too.
