I can see Sony maintaining a 2:1 sales advantage for this upcoming gen. PS5 at 120/130 Million versus the Xbox Series X at 60/70 Million.
Even if you assume MS will take back NA/UK with a cheaper model on the market, they won't be dominating those regions like they did in the 360 era. PS4/XOne sales in NA are relatively close this gen. Worldwide is where MS has to improve to prevent another 2:1 from happening.
One thing to keep track of will be RoTW markets where Sony has an uncontested market to grow and expand their brand.







