This was a teamgame tournament. Cybran is just terrible in teamgames, the faction is heavily frontloaded for t1 stage raiding which just doesn't happen in teamgames.
Of course UEF and Cybran get picked more in casual games because it's just the default factions. Aeon and Sera were always like 20% of the faction pick and Cyb and UEF were like 30%. Most people just don't care about what is actually good and can't tell how to actually use what is good.
Back when Cybran was insane OP, 19 of the top 20 ladder players strictly used Cybran. It didn't really change that a ton of people played UEF in casual games and the overall preferences across the playerbase stayed the same.
I strictly play UEF in casual games. For this tournament I rolled almost entirely Aeon.