About 50m, maybe a little less or a little more. I can't see them doing much better than that since they have basically given up on making first party games. Every first party game shown at E3 will be for the Next Box. Don't expect any more first party games for the XB1 except for maybe Forza.
curl-6 bet me that PS5 + X|S sales would reach 56m before year end 2023 and he was right.
My Bet With curl-6
My Threads:
Master Thread, Game of the Year/Decade
Switch Will Be #1 All Time
Zelda Will Outsell Mario (Achieved)
How Much Will MH Rise sell?
My Bet With Metallox