There is a chance that the only reason why there are two adjacent seats left on the seat map *at all* is because American charges for certain seat assignments. That gives the people who really care about sitting next to each other the chance to make that choice for themselves rather than show up late in the booking cycle and have more of the seat assignments taken by people who do not value them as much.

So the $25 isn't really the impediment to sitting together, it is the enabler to sitting together.