This is a bad analogy because the hardware in engines of today is actually not that different or hard to work on fundamentally, but manufacturers do intentionally lock down software to make diagnostics very tricky. They became more efficient and complex, but people still hack on even the most modern engines, usually by tossing the OEM software.

Aftermarket ECUs (even the open source ones like rusEFI and speeduino) show that you can actually do the stuff required to make modern engines go vroom, but manufacturers have no desire to make that process easy out of the box.