Proprietary SOCs suck when you run into a bug in system bring-up (and if you are going off the beaten track even a little, you will), and you have a vendor that:
- Doesn't believe you. In fact, is quite vocal about not believing you.
- Takes your hard-won repro code (with "a possible workaround, what do you think?") and is silent for months;
- Finally publishes a TR about that bug, along with your very own workaround code, verbatim and unattributed and you never even got an email acknowledging the issue.
... and after nearly a year of chasing the stupid thing down, as a last resort grants you a five minute phone audience with the chip designer. Sixty seconds into the problem description he says, "Oh, I know what's going on..." and proceeds to fix everything by telling you what parts of the documentation are lies. Your workaround turns out to be how you have to do it. You feel a little ill.
An open source SOC would not necessarily be better understood by more people, but it probably couldn't be worse.