I think I could be very good on-air but I would need a good partner so that we can bounce things off each other, like Mystery Science Theater. I would also demand our silhouettes be shown on the bottom:
If you are talking about high level, like ESPN, then it seems most are former players or top coaches who are retired. If you are young just starting out, then college radio broadcasts might be a good way to gain some experience and pad your resume.
If you are thinking about this for yourself, then know that there are multiple positions on broadcast teams.
You may just want to get into it for volleyball only. In that case, you would be aiming to be what's known as an analyst or color commentator. This is generally the 2nd chair where you are led through the show by your partner and you add color and depth to the broadcast through your sport specific knowledge. Could be just seasonal or limited to one team, area, or conference.
Full-time work goes to the play by play announcers who are first chair, lead the broadcast, read the promos, take the audience in and out of breaks etc. They call the action and most work multiple sports.
Then there's the sideline reporter....
VolleyTalk is my favorite literary device. And I eat babies.