Pretty bad practices by Microsoft and sounds like that has a decent chance of costing them money in the EU. However I think the point that having one monopoly

Pretty bad practices by Microsoft and sounds like that has a decent chance of costing them money in the EU. However I think the point that having one monopoly AV decreases security because the bad guys can adapt to it is at least not as clear cut as it seems. Especially compared to the scenario of someone having multiple AV programs installed. AV programs themselves are excellent attack vectors, especially for the more skilled attackers so reducing the number has at least some theoretical benefit.