There is no mystery here.
Yes Marconi was an inventor but he did not invent radio nor did he claim to. While a teenager in the late 1800s, Marconi read all that was being published about generating electricity and the newly discovered “Hertzian waves”. He then used his inventive genius and superior machanical ability to make it better. He was not a scientist and had no scientific training. In fact, he readily admitted he did not know how these “Hertzian waves” travelled through the air and over the horizon. Even so, his reputation as the leader in wireless communications was spreading even before he sent the first radio signal across the Atlantic in 1901.
To say Marconi invented radio is like saying Henry Ford invented the automobile. It was a combination of the work of people like Faraday, Hertz, Maxwell and many others. Marconi just put it all together better than anyone else.