Because making tens of millions just wasn't enough it seems
Unity Bosses Sold Stock Ahead Of Scummy Dev Fees Announcement
KOTAKU.COM
CEO John Riccitiello sold 2,000 shares a week before Unity revealed its Runtime Fee
It's gonna hit indie developers hardest and even some may end up pulling their games from sale. Unity is not small fry either - 37,000 games on Steam are made with the engine compared to 10,000 using Unreal. There's almost 750,000 products using Unity too so it's not like they need extra dosh for RnD or to compete with rivals. With Steam and other DRM holders taking 30%, it's really adds up.
Lots of feedback here
'An astonishing scumbag move': Indie developers react to surprise Unity engine pricing changes | PC Gamer
WWW.PCGAMER.COM
Unity's new Runtime Fee will charge developers on a per-install basis.
And this is hilarious