I wonder if this is a a case of the polymer breaking down over the years?
Generally speaking, head gaskets don't just give up!
They mostly fail due to:
* Overheating.
* Studs stretching.
* Cylinder liner heights uneven.
* Corrosion of the mating surfaces of the block and head itself.
* Poor alignment and fretting due to inferior location dowels.
* Poor practice when assembling the engine.
* Differing expansion rates of different materials used in the construction of the engine (this last one applies to engines with iron blocks and alloy heads. Not applicable for our cars, but I've included it anyway, as a general guide.)
Even gaskets made from inferior materials, rarely just fail without an underlying cause, they do, however, suffer failure more easily when something goes wrong as they have a lower tolerance to overheating etc.
You do of course realise, that your temp gauge sender's probe needs to be immersed in coolant to work properly, so overheating due to a lack of coolant won't necessarily show on the gauge.