Complex sentence: It quickly gained significant Poland-wide popularity; as many still did not have television sets, around the late time when the show aired, families and friends congregated in the houses where the show could be watched.
Split into simpler sentences: It quickly gained significant Poland-wide popularity; even though many people still did not own TV sets. During the late-night hours when the programme was aired, families and friends congregated in the houses where the show could be watched.