As an engineer who has designed IC-based systems (and control software), I just do not believe that half the cost will be in those areas. Initially, software is very expensive, but over time, that will drop quite a bit.

The semiconductors are already all over the place. There are little computers (Systems On Chip) SOC's - often costing well under $1.00 each, so that, for example, each window motor might be controlled by one. In other words, in current cars, they are everywhere.

An electric car may or may not require more. It requires more power electronics, for sure, because it must transform the battery DC supply into the waveforms the motors need, and that is done at very high power levels. But, there is great progress there, with remarkably high power transistor switches available (I'm not up to date with the exact power levels, but I've read about the technology changes and seen surprising power levels).

Beyond those high power engine control circuits, there is control circuitry, but that's just typical real-time computer technology (with, as I wrote before) higher than normal environmental tolerance.

But consider this: I have a DJI drone - a Mavic Pro - relatively small, under $1000 drone.

It has four motors, which together are around 1/4 horsepower. It has a control systems that has to be quite complex - unlike a car, it moves in three dimensions, and it is the Motors that control the motion and stability.

And yet, both the power electronics and that control system probably weigh less than 100g and cannot be terribly expensive.