Excaliber became ineffective in Ukraine after Russia deployed effective jamming.

War games can be very deceptive though. Back in 2019/20, 2 separate studies ( Polish and US) expected that it would only take Russia 4-5 days to get to Warsaw with Polish units sent to the border suffering 60-80% casualties.

To be fair NATO wasn’t taking really taking defense that seriously back and maybe they had a point, although considering what happened in Ukraine that seem like a very unlikely outcome (unless Britain/France/Germany decided to stay out and not risk their air forces ..)

I guess overestimating your opponents is usually better than the opposite. OTH had Britain/France not made that mistake in the 30s much of WW2 could have been prevented.

The purpose of wargames is to find holes in your defense and the shore them up. If your war game doesn't find holes you are probably doing it wrong. In the real world your enemy doesn't have spies everywhere, but in a war game you should give them spies everywhere just because you won't know where those spies are and so everything could be compromised.

Russia didn’t overrun Ukraine quickly because they voluntarily withdrew for peace talks.