As should be apparent, Oracle is focused on the high-end server market and those that have strict reliability and high scalability requirements; inevitably, that means that much of the community that is focused on commodity hardware is going to be less interested given pricing and focus.
I'm not sure what open source packaging projects you're referring to; the image packaging system itself is still quite alive and still open source and available at https://java.net/projects/ips
If you're referring to the general availability of open source software on Solaris, the reality is that the vast majority of compiles and works on Solaris. A large amount of effort has gone into and continues to go into making it easier to build and use general FOSS on Solaris.
In addition to that, based on customer demand and business requirements, FOSS components are integrated into Solaris and updated.
As for "completely ridiculous choice", I think that's an odd thing to say. Solaris has zones, ZFS, image packaging, openstack, and many other compelling technologies (third party or otherwise) that are still being actively developed and improved. Performance and reliability are pretty important attributes for an operating system.