Personally, I can't imagine what use a solid state
circuit board is in an electric oven. Regular
mechanical switches, clocks, and thermostat.
Nobody (almost nobody) ever uses the clock so what
need is there for a circuit board?

Once you design it so that the elements are controlled by the "circuit
board" all kinds of functions become a whole lot less expensive.
Controlling the self-cleaning feature uses the same temperature sensor
that's already in place. The only "extra" is a small electro-magnet and a
switch to keep the oven locked.

I strongly suspect that with a reasonable run, it's as cheap to make a stove
with the timer and electronics as a more electro-mechanical self-cleaning
over.

The only problem is that when the board goes, it's gone.

I suppose it's still possible to get a truly "basic" stove with
electro-mechnical thermostat and no self-cleaning features. But once you
toss in the self-cleaning features the electronics is not much more
expensive than basic electro-mechanical controls and you get the timer
function (and clock) for only a little more cost.

I still remember the old mechanical timers. It always seemed that by the
time I got around to actually using it, the timer had worn out!