It's a rubbish analogy, because deterrence with nuclear weapons is effective - because nobody dies,
deterrence, where everyone is armed with guns is ineffective, because 30k people a year die.
Figures like that are misleading. It implies 30K wilful homicides.
This is not the case,
The majority of Gun deaths in the USA are actually suicides. less than a third of "Gun Deaths" are criminal homicides. Obviously if guns are readily available they are likely to be the method of choice for depressed people.
The USA's suicide rate is higher than the UK's but it is not exceptional, there is no evidence to suggest that the availability of firearms makes suicide significantly more likely in the US than elsewhere in the developed world
There are many European countries with higher suicide rates than the US, despite far stricter gun controls.
Of the gun deaths that are wilful homicides, they make up around 2/3 of all homicides. Yes, despite the ready availability of firearms, a third of US Homicides actually involve some other method. (Stabbing, strangling and so on)
Furthermore some 3/4 of US homicides take place during the commission of some other felony (Burglary/Robbery etc)
It is tempting to argue that if one snapped ones fingers and made all the civilian guns in the US disappear that 30K/a would no longer die but it would almost certainly be wrong.
It might make a slight difference, but in the main, Suicides will still suicide, they will just find a different way of doing it.
And Robbers will not give up the life of crime and stay at home, They will (as many already do) just use knives etc instead.
And the handful of people each year who go Postal and decide to destroy a School or a nightclub will use home made explosives/Poison gas/whatever. Obviously, this is harder than using a readily available firearm, but not that much harder and almost certainly not so hard as to put them off.