From what I have heard, a bishop with an SSPX presence in his diocese will often encourage the FSSP or ICKSP to open a church in order to siphon members from the SSPX. (Apparently, lay people are quite willing to leave an SSPX parish although outside of the original group who left at the time the FSSP was founded, none of the SSPX's ordained clergy has taken this step.)
Whether this is part of a greater plan to eventually close the doors on the FSSP or IKSP, I really don't know. While we tend to paint the Catholic hierarchy in this country with a pretty broad brush, there are bishops who have been quite supportive of their Latin Mass communities, and have really left them alone.