OBDII is only a minimal standard, compliance requires only reporting that is related to emissions systems and engine systems that affect emissions. Basically everything else is manufacturer-specific and requires either a manufacturer diagnostic computer (every manufacturer has one) or third-party software with (usually reverse engineered) support for manufacturer diagnostics. Since CANbus became the normal implementation for OBDII, much of this is done by communicating with individual modules over OBDII using message sets proprietary to the manufacturer of that module. Newer vehicles incorporate more and more functionality into these modules, such that the usefulness of the core OBDII set tends to decrease.

OBDII is really quite far from solving the problem - unsurprising because it wasn't intended to. It's an emissions standard, not a general diagnostics standard. Common modern fault points like the brake system and SRS are unaddressed by OBDII, and that's without getting into infotainment and telematics.