i dont really think a mad strategy would end all life on earth nor would i think that there would be zero survivors. it would suck for them, blotting out their sun and making their balls not work. but there will be people alive after the fact. so i think its an awesome strategy, and i think it would be awesome if we carried it out from time to time.
It wouldn't even have a 50% casualty rate for the initial bombings. Many more people would end up dying in the aftermath due to disease, lack of food, and fallout. The fallout zones would remain impossible to move across for a couple of months afterwards, and you wouldn't want to spend any real amount of time in them for another few years. The groundbursts necessary to eliminate targets even as soft as railyards and such ensure this; imagine Chernobyl on a much larger scale with much more and nastier, longer-lived fallout. For each initiation.
Due to the distribution in targets in any industrialized country, large portions of the targeted nations would remain impassable for those few months following the week of the war. This causes society in those nations to break down rather precipitously. Modern industrial civilization would break down even in nations which were not targeted at all. This is because of the interconnectedness of the global economy, even at the time. For example, making modern computer chips requires very precise optics, among many other precision tools. You know who makes those? Only the US, Japan, and Germany. That's
it. You know who makes almost all the precision machine tools in the world? Germany. Once those sources are gone, and the tooling begins to break down, it will not be back for a long, long time. Air travel and such would shut down within a year or two, as spares are exhausted. The factories where those parts were made and assembled, with all their precision tooling and such, were almost exclusively in Europe (Airbus) or the US (Boeing). They of course would have been hit on day one. Just about every high-tech, or even not so high-tech, good in the modern world is like this. Industrial civilization wouldn't completely disappear in countries that weren't bombed, but it would regress at least 50-100 years.
In day seven, most people would have just mentally collapsed.
MAD strategy is indeed mad. It makes perfect logical sense, so for that reason it was a lunatic strategy. Only madmen use logic to this extreme. Humans should not be expected to behave rationally. What happens if someone makes a mistake? What happens if some really mad person takes charge? Game Theory only works if the players are fully rational, and we are ****ing humanoids! This MAD **** was built for the robot era, not for the homo sapiens era. Thank goodness we survive such madness...
MAD is predicated on one simple truth: humans wish to stay alive and in power. Give anyone who is not in fact mentally ill the reins of a nuclear power, and he will not get anywhere close to using nuclear weapons in any form, except if his country is getting destroyed anyway. Even a place like Pakistan, easily the most unstable nuclear power, does this. They may rattle sabers against India, and India rattles them back, but war with India has been off the table ever since both of them acquired the bomb. If they did not have successful nuclear programs, I imagine we'd have seen a major conventional war between them at some point, or would in the future. The advent of nuclear weapons has effectively ended the era of war between the great powers because of the ability of nukes to utterly destroy nations in a single night.
