I mean, they've done a good chunk of contribution to open source; they're one of the biggest contributors to Cassandra, for example. I believe they also contribute a lot to the FreeBSD kernel.
But I more or less agree; Apple kind of likes to "open shit up and then forget about it" a lot.
Yeah Apple are just fantastic stewards of open standards, as can be seen from the amazing job they did with OpenCL...
Still so angry at Apple and Nvidia for that.