When Atticus went to Montgomery "to read law," what tradition was broken according to the narrative of To Kill a Mockingbird?

When Atticus Finch left Finch Landing for Montgomery in order to study law while his younger brother Jack went to Boston to study medicine, the tradition of male Finches living on Finch's Landing was broken. Only their sister Alexandra remained there. 

Scout narrates that her Aunt Alexandra married a rather phlegmatic man, who mostly lay in his hammock by the river watching his trout-lines, quite unlike the ancestral patriarch of the family, Simon Finch, "a fur-trapping apothecary" from Cornwall, England.
Simon Finch came to America because of religious persecution. First, he came across the Alantic Ocean to Philadelphia, then down the Atlantic all the way to Jamaica in the Caribbean Sea and on up to Mobile, Alabama, on the Gulf of Mexico. From there, he wandered in a northerly direction from Mobile on the Alabama River about forty miles from the old Spanish settlement of St. Stephens. At this location he established a homestead on the banks of the river, a location nearly forty miles from St. Stephens, in which he had found a bride.