The Kobe crash could have been prevented by many things. Existing synthetic vision systems would have easily prevented this. They're not even that expensive -

The Kobe crash could have been prevented by many things. Existing synthetic vision systems would have easily prevented this. They're not even that expensive - built in systems can be had for a few tens of thousands of dollars, or non-certified iPad based systems for a few hundred. That crash was likely due to disorientation in dense fog with an experienced, IFR rated pilot but who didn't experience much fog in LA. A radar altimeter would have been unlikely to help.