Re: 2 Gig?
It's not difficult. To make components rad-hard you need to thicken the oxide (reduces the risk of punch-through and is more likely to survive the ionisation track of a cosmic ray scatter particle) and increase the surface area (thicker oxide means less capacitance, more area increases it, and you want the highest capacitance in your cell to reduce the chance of a small stray particle flipping a bit. ECC can only go so far.)
IBM have produced a range of industrial-strength PPC processors for a long time with thicker gate oxide etc., and military design just takes this further, along with the more exotic substrates like SoS which are better able to resist distortion and conduct heat.
There were also completely non-cmos processors using a bipolar technology, but the problem with them is that they use a fair bit of power just standing still as current is needed to maintain the logic states rather than voltage.
So "radiation-toughened" isn't really quite correct. Rad-hard components are fundamentally rather different designs produced on different production lines. They cost a lot more to produce, partly because of the low production volumes but partly because a huge amount of inspection and testing is needed.
The "consumer-grade" stuff isn't junk; just designed for a different purpose. If you want JAN-TXV components in your phone, you won't have to worry about lack of network capacity because only bankers will be able to afford them.