RCA was created by the government during or just after WWI because there was fear that the British Marconi company was going to have too much influence in radio communications. Then KDKA in Pittsburg came on the air under the auspices of Westinghouse, and W. saw from all the cards and letters coming in that there was an interested if amateur audience out there who had built their own sets. They figured that plenty of people who were not technically bent would want to purchase ready-built receivers so seized the opportunity and started making simple crystal and one tube sets, and on it went. In the beginning RCA was just a holder of patents and G.E. and Westinghouse did the actual manufacturing. You'll find some of those early sets with either Westinghouse or RCA names on them.
A very interesting website on which one can spend many hours is:
http://earlyradiohistory.us/index.html