They have to continue fighting or they would give up.
But I think they are going to struggle to win any month this year. Their line up is weak for major exclusives (same as Sony), they have a single game exclusive more than Sony this Xmas (AAA) and thats only because they haven't had as many exclusives in the year.
Unfortunately Sunset Overdrive - i don't see it doing that well, Forza will do fine and Halo will do best, but i cannot see it pushing significantly more than Sony, especially as September will be in Sony's favour big time because of Destiny..that will push a lot of users and their friends to PS4.
In terms if AC Unity, one of the reasons why Sony didn't need to back it this year (so they could put money into Destiny) is that the more serious AC players already moved to nextgen last year for BlackFlag.
Sony always does well early in the year, and with Bloodbourne and The Order in the first part of the year, again they will be pushing well. It doesn't sound good for MS.. they have games in dev but they seem way off, looks like they blew their cards early and now have not much coming up.