Tony writes:

If one sets 'realism' to high in a sim, does one
get those kinds of failures as often as they might happen with a
general aviation aircraft?

Simulators (including MSFS) usually allow failures to be adjusted
independently of overall realism. So you can have anything from a 100%
reliable aircraft to one that experiences multiple catastrophic failures even
before pushback. Many types of failures are so impractical or dangerous to
practice in real life that they can only be experienced safely and
economically in a simulator.

Does the weather go marginal, does ice grow
on the wings, vac pumps fail, those sort of things that most of us who
have been pilots for a few hundred hours have experienced?

This is also controllable in a sim.

Oh? you can get them in a sim if you program them in?

It's a parameter setting rather than a programming problem.

Actual airplanes
do allow us to simulate emergencies, but in real life sometimes it's
not a simulation.

The most critical emergencies cannot be practiced outside of a simulator,
because they are too dangerous or expensive. You either learn to handle them
in a simulator, or you don't learn to handle them.

Airline pilots practice engine failures regularly in simulators, even though
most of them will never see a real-world engine failure during their careers.

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