Interestingly the wing fold occurs automatically on the landing roll out below 50kts, with the idea being that by the time you vacate they have folded. Smart idea.
Extending them though is down to the pilots and although it’ll be impossible to depart without them extended (EICAS) it seems like a bit of a headache to pick a time to do it. The current trend is towards doing all the flappy bits at the gate having pushed back, but the wing unfold will need to be done later in the taxi in some tighter places. They take 20 seconds to lock into place so need a bit of time.
In a world of single engine taxi and MRO and all the other guff, worrying about banging the wingtips onto someone on the taxi out in the dark is another one for list!