you miss that i was talking about 650km/h "drones" (because, yes, it was already 3rd year of war, and 200km/h drone like Shahed became much easier target - this is why Russia has started to also use the 600km/h modification of Shahed with RC jet engine). There is related discussion under that comment addressing your point about interception.

>Both countries do the type of attack drone clustering you suggest

Ukraine still isn't completely there. They do attack Russia with up to 200 drones/day. They seem to never cluster more than a few, and the drones they are using are comparably small - 50kg warhead - and slow, 100+ km/h, almost always less than 200km/h. So they are easy to intercept/shoot down, almost never penetrate Moscow air defense, and do noticeable damage only when hitting flammable targets like oil/gas industry related.