If there had never been a referendum on EU membership, Britain would still be divided between “remainers” and “leavers”. They would just be called something else. Terms coined for a one-off ballot describe differences that were revealed, not invented, by the plebiscite.
Brexit redrew the political map along axes of culture, geography, class, age and educational attainment. City-dwelling professionals who went to university overwhelmingly voted remain; older, manual workers who left school at 16 and live in small towns generally backed leave.