How did everyone immediately know the HMS Dreadnought (1906) changed the game?

by Lord_GP340

I keep hearing about how when the HMS Dreadnought was launched, all previously built battleships became obsolete on the spot and it basically reset the Anglo-German naval arms race. But AFAIK the British fought no naval battle from its launch until 1914, so how was the total superiority of going all-in on big guns instead of having lots of guns of different calibers, like it was the practice before, immediately apparent to everyone?

thefourthmaninaboat

While more can always be said, I've previously answered a similar question here.