Time will tell that´s for sure but I fear that if they completely withdraw every support from MP then a lot of MP player will just stop caring about it altogether.
Seriously there are lots of people like me who like to log-in to MP every weekend to do those challenges and not care about it the rest of the week. Now if you take away those weekend challenges then there won´t be much left for those people to come back and combined with no additional content to make things fun again (DLCs, patches) does not help in extending the MP lifecycle.
Using the past weekend challenges however would greatly help in extending the lifecycle because there are a lot of player which have not completed certain past challenges and would gladly do the new ones again.
A loop of past weekend challenges is a win/win situation for both BW and the playerbase.