How did some radio shows come to be nicknamed soap operas?

In the 1920s, the radio industry wanted to get advertisers to increase their station ratings and by extension, their profits. They wanted to appeal to the house hold audiences, so contacted businesses selling house hold items about sponsorship. One of the first businesses to sponsor the radio dramas was a soap powder producing company, Procter and Gamble, who sponsored and produced several radio dramas which were nicknamed 'Soap Operas'. They were so successful that radio dramas in general became known as Soap operas as well.