Static will damage sensitive devices like transistors and will easily kill some devices like MOSFET. However, it's not that easy. Firstly, when soldered onto something conductive, devices become less sensitive to static because the conductor around them takes some of the punishment.
Also, circuit designers aren't *****s. There is similar phenomena (i think it's called transient state in english) when something changes in a circuit (like disconnecting a load), which can produce similar spikes in current. Damn i'm technical. The idea is the circuits are somewhat protected from discharges.
Furthermore: plastic is an insulator. It shields from static. Sure, when charged enough it will become a hazard, but it's not that easy to do it accidentally. That's why you had to stand on plastic things in the experiment: to prevent the electricity going to the ground when you touched the magic (charged) ball
Even more: the mic is tucked inside. Static has a tendency to jump for the nearest conductive surface. The screen is somewhat conductive (remember that it works by changing resistance, so it can't be a perfect insulator), the discharge would kill it more easily.
Bottom line: it's not technically impossible to fry the transistor/amplifier (not the mic itself - those are sturdy), but it's more likely that evil gremlins dismantled your device mid-shipping and replaced the mic with alien eggs