You're missing the point. Russia simply lacks the conventional missile production capacity necessary to flatten Kyiv. They used up most of their missile reserves early in the war and are now firing them off about as fast as they can build new ones. And it's not clear that they're able to accurately target individual buildings; some of those strikes appear to be random collateral damage. Russia is simply no longer capable of large-scale precision manufacturing; it's a relatively poor country with a broken tertiary education system and most of the foreign experts left years ago.