...what does it all mean

It means that as the transistors get ever smaller, their reliability becomes more of a gamble. Voltage spikes, cosmic rays, quantum effects & International Terrorists[1] mean that the MTBF falls sharply compared to 'old' 100nm fabrication, and perhaps more worryingly 'failure' may no longer mean 'works/is dead', but might mean 'once per 100-million clock cycles, you'll get a dodgy data value'. Not sure I'd want to be on an aircraft where a 32nm CPU was making important decisions.

[1] I might have made that bit up.