Sony have a lot of fans, so i expect Sony to still have a lead next gen. But all things considered, i think this race will be incredibly close. The closest weve ever seen.
First of all in terms of console sales, yes, MS will undoubtedly "lose" some console customers that will just stick to the PC instead. Thats an option now. But in terms of overall game sales, i dont think MS will lose any. I fact i think they will be higher than ever. PC + xbox one + XSX = a lot more potential people this time around.
When MS were dominant in the console market with the 360, Sony had screwed up their launch. They were arrogant and it was too expensive. That wont happen this time around.
When Sony dominated with ps4, MS had screwed up their launch. They did not put gamers first, the hardware was weak and more expensive. That wont happen this time around.
I fully expect this next gen race to be the closest weve ever seen, and thats a good thing.