There really are not as many people as you think who are nuts enough to try anything excessively dangerous. You will see many pictures of routes or ventures that show someone free soloing; but in reality they are running something more like bouldering (climbing without ropes/harness but are only a couple tens of feet high often times). Pictures can be taken from an angle to make you believe it is far more dangerous than it is.

That said, of those who actually do free solo climbing, death is (I would argue) more uncommon than you are likely to expect. This has to do with the fact that the routes free solo climbers usually run are the ones that they are incredibly familiar with and/or are not particularly difficult for their skill level. There are two very notable and incredible climbers who have indeed died during climbs however; John Bachar and Derek Hersey (I highly recommend watching parts 1-3 of Dereks documentary). Other than that, climbers that die from Free Soloing who are not big names don't hit the papers as having died specifically from Free Soloing so it's hard to say just how common it really is.

Here (4:34) is a pretty nifty montage of well known free solo climbers you might find interesting.