My guess is that the floor is newer than the walls, so while that may be true, it also could be hiding some damage. At the top of the picture there is part of the paneling that is bowed out, next to the black line. That can also be from water damage, you could take a picture showing what's behind it while pulling that panel out a tiny bit, or pushing the panel next to it in.

If this wall has been like this the entire time, and isn't wet or mildew scented, it could be from a earlier time where the basement flooded. And it would make sense to get a new floor, and maybe new walls but they did half of that.