Southold Town, with 25,000 year-round residents, has always had a vibrant retail scene, Mr. Russell said. “If there is any change in retailing, it’s that it is actually being replaced to some extent by these boutique-style specialty food shops and restaurants like you see on Love Lane,” he said, referring to a one-block stretch in Mattituck that features a cheese shop, a knitting store and the always-busy Love Lane Kitchen, where you can get a bowl of steel-cut oatmeal for $8. He noted, too, that many of the newer businesses are taking over spaces that had been occupied by decades-old businesses. “Is that really an increase in retailing?” he asked.

Some residents have mixed emotions about the changes — even those who have benefited from them. Lori Guyer, the proprietor of White Flower Farmhouse, a boutique in Southold filled with linens and milk jars, said she had seen enough of an uptick in business that she now stays open year-round. “We never used to open in the winter,” she said, but now, “I stock the store with Christmas inventory.” There is a part of Ms. Guyer, though, that longs for the days when the North Fork was a little sleepier and she could take the winter off.

As for Einstein Square, the developers hope to capitalize on the building’s history. In the summer of 1939, David Rothman, who founded Rothman’s Department Store, was minding his shop when Mr. Einstein, who was renting nearby, came in to buy a pair of sandals. Because of his strong accent, Mr. Rothman thought the scientist was asking for “sundials.” When Mr. Einstein pointed to his feet, however, the misunderstanding was quickly rectified and he left the store with new summer footwear.