I would imagine (despite being a "two team studio") a considerable amount of the workforce is now on TLOU 2. They've said in the past that they will mould their teams to whatever the studio needs. i.e. they're not necessarily always working on two games.
It's possible they know what Straley's game might be before he comes back as well so pre-production for another title is possible. They've already visited space launch stations as a studio together.
It's possible they know what Straley's game might be before he comes back as well so pre-production for another title is possible. They've already visited space launch stations as a studio together.