Were any of the games broadcast on the radio? I am unaware of any. But then, I hadn't been paying a ton of attention to the XFL.
My guess is that the XFL has no national radio contract yet. SiriusXM went the "television on the radio" route, carrying audio from the telecasts of all four games. TV sports audio generally doesn't translate well to radio, and this weekend's simulcasts were no exception -- too much talking about something else when plays were going on, lack of detail on the plays that did get called, announcers reacting to things the radio audience had no way of seeing, etc. This is the way SXM "covers" Champions League soccer, and it doesn't work there either, long stretches of crowd noise and announcers just ticking off the names of players as they touched the ball with no indication on where on the field the action was happening.