Switch is at 35M, and will be at 55M+ when ps5 and xbox4 launch.
Hard to believe xbox4 will pass 55M with all the focus in services instead of hardware (with games in other plataforms, xcloud available elsewhere).
Even hard to think it would pass switch lifetime.
If ps5 keeps the ps4 trajectory, yeah it would pass switch. But is still too soon to predict anything, no infos, price, library, no clue about acceptance of stadia/apple/xcloud and how it would impact ps5...
for now: switch/ps5>xbox4