Notice how in the current war in Europe Russia is not using ICBMs or nuclear torpedoes, and the bulk of the damage is dealt by vast numbers of small, cheap, subsonic drones, and a few medium-range missiles (some made by North Korea, of all places).

Losing the ability to watch and intercept "obsolete" weapons is quite risky. In 1960s, some cool newest-generation supersonic jet fighters got rid of cannons, because rockets felt so much more efficient. Using them in actual warfare quickly showed that rockets are not perfect, and expensive; you can run out of them, and become helpless.