The word "were widespread" can be paired with several antonyms, including "were uncommon," "were isolated," "were localized," "were scarce," "were limited," "were rare," "were sporadic," and "were infrequent." These antonyms denote a lack of prevalence or distribution of something, contrasting with the ubiquitous or extensive distribution implied by "were widespread." In other words, the antonyms suggest a situation where something occurs or exists in small or specific areas, rather than being widespread or prevalent everywhere. The choice of an antonym depends on the context and the degree of contrast one wants to emphasize with "were widespread.