If all you need is a working head unit you should be able to get that for <$1000.
It's still an investment, but nowhere near $30k.
The real reason nobody bothers with this is that it's just the infotainment, and if you really want a custom one you can just buy a new head unit, or glue a tablet where the existing one resides.
You won't get access to the engage electronics, emissions controls etc. Those are all other dedicated computers.
