This is a bit broad, but essentially there are issues that we have in society that end up costing tax payers, and individuals a lot of money, or are simply really inefficient. Education is one such thing, but you could also branch out into other issues such as theft, health care, environmental issues. You can see that there are certain companies that are helping to tackle these issues in various roundabout ways, but…
All of those are public goods/tragedy of the commons issues operating in highly political regulated environments. Very difficult for a startup to make a difference there in a way that can make a return.
Theft on the other hand is gradually being diminished by technology: the same omnisurveillance of always-on IoT devices makes it easier to remote-brick them or find their location if they're stolen. The problem shifts to hacking and ransomware.