You can be pretty confident that GW will support it through 10th, but the real question is whether you'll be able to find anyone to play it with. They're also releasing this Combat Patrol mode as another 500-point "mini-40k" game that uses set armies, many of which aren't compatible with BA because they contain vehicles and what have you, and it'll probably require a lot less setup time than BA with its interlocking terrain pieces. Lots of us are as apprehensive about the terrain buy-in as you are - nobody wants to shell out for this stuff if nobody else at the FLGS is going to be interested in clipping a bunch of walls together when they could just chuck a few shipping containers on the table and jump into a Combat Patrol game instead. Me personally, I'm gonna get one of these MDF terrain kits.