It's specifically Sony's share in Europe (if you exclude Nintendo).Then it's odd to only say over a decade. If she's ignoring Nintendo then Sony has been the dominant console leader for nearly three decades in Europe.
I'm pretty sure MS was arguing that if Nintendo is part of the same market, then they're proof you don't need CoD to compete.
And that if they weren't part of the same market, then Sony owns 80% of the market.
Also is the cma focusing on Europe as a whole or just the UK with this investigation? Xbox sells pretty well in the UK.