Too close for profit

Can somebody explain to me the rationale of having two supermarkets of the same chain not six blocks apart? And one of them where there is basically no available public transportation in sight? It doesn't seem like it could be at all financially viable.

Moreover, they are not even maintained in the same state of repair. The one that is less T-accessible looks downright sketchy, even though it's actually not all that far away from Harvard or Porter Square. If they spruced it up a bit, they'd probably get more business from nearby neighborhoods, who would otherwise just flock to the Porter Square location.