The North Korean stakeholders both inside and outside the regime understand how tailored it is to needing a member of the Kim family at the top. The destabilization is something they fear tremendously. There's a lot of inertia here and many structural problems to changing.

There are groups though that do what you're suggesting with balloons. News does get into North Korea in small doses - but nothing like to the degree it used to get into the Eastern block. It's much more locked down.