Fullwings,
I agree extreme windshear is a possibility. I said it was very rare, not impossible.
The >100kts shear in the sim you mention is relating to a microbusrt. A phenomenon which, it is generally accepted, will create conditions outside the capability of most if not all aircraft. Hence the advice to avoid them entirely. There isn't much point in including them in this discussion as there really isn't any decent way out. If you are at final approach speed and you encounter >100kt shear, you're dead, and quickly. (I accept that the 100 knot reduction comes just after a significant increase in airspeed as you enter the outflow, so you are unlikely to be at final approach speed)
In my mind and for my posts, I have considered windshear to be a sudden and lasting change in wind direction or speed which results in a
sustained loss or gain of airspeed. Low level turbulence does not fall into that category.
Anyhoo, very interesting thread so far!! Keep it up everyone!