They care so much for open source that they instantly killed OpenSolaris even if that led to much of the team quitting.
They also very much care to create an open and competitive environment, that's why their reps repeatedly refused to sell us licenses to have Solaris run under VMWare ESXi, demanding we replace our ESXi deployments with... VirtualBox (no, really).
Honestly, what was the point of continuing to fund OpenSolaris? Tiny market share, no prospects for improvement. They're already funding a different open source operating system.
Caring about open source isn't about funding infinite options everywhere.
They kept developing and selling Solaris and OpenSolaris kept the team happy. I doubt it was going to be that expensive on their part, especially if they could use Solaris sales to fund it.
Also part of OpenSolaris was OpenZFS, used in many NAS systems worldwide. When they killed OpenSolaris the ZFS people also left Oracle.
They also very much care to create an open and competitive environment, that's why their reps repeatedly refused to sell us licenses to have Solaris run under VMWare ESXi, demanding we replace our ESXi deployments with... VirtualBox (no, really).