> If MAD is disrupted by groundbreaking tech, and if this technology would significantly boost strike capabilities and possibly render nuclear weapons useless,

> If MAD is disrupted by groundbreaking tech, and if this technology would significantly boost strike capabilities and possibly render nuclear weapons useless, then the rival nations would be forced to exercise a nuclear strike preemptively to ensure their security to prevent a war they would inevitably lose. As of now, a nuclear war would result in two losers anyway, that's the whole point of MAD. Doing a preemptive strike would just create a massive problem where there might never be one. The only reason to attack would be if you already plan on kamikaze-by-nuke.