He doesn't think XBO will make any type of comeback. He just says that being in second place makes them more willing to try different things. Whether or not being in second place was the reason for Sony's creativity last gen is something that can't be proven, though. They did make a lot of changes, mostly for the better, though.
I think it's like Nintendo having to rethink their strategy after the GameCube and WiiU to win back fans. Then again, who knows how many years in advance companies have to work to put out a project? Anything M$, Sony, or Nintendo do to " make a comeback" could possibly be something they were planning to do anyway.
At the rate that Xbox One is being outsold by Switch, I think Switch will move into 2nd place and Xbox One will stay firmly in 3rd. Could Switch surpass PS4, it is possible, but right now the numbers don't indicate they could catch up for at least 4-5 years, by which time the generation will be over.
So with Xbox coming in 2nd last generation, after a sizable lead on the PS3, and 2nd again the previous generation to that and either 2nd of 3rd this generation will Microsoft have the staying power to invest in Xbox for a 4th generation? Microsoft's lack of staying power (see Zune, Windows Phone etc) would suggest they might give up and just focus on PC game. Maybe rebrand PCs as Xbox and not have a dedicated console next gen?? OR just crazy thoughts?