Most people think science is just about facts or just about knowing something. That is a sad misconception. Sometimes not knowing is the best thing that can happen to a scientist. Stars like the sun don't die quietly.
Planetary nebulae have nothing to do with planets.
The name just stuck. PN are special because they are big and easy to observe. In the years since the Hubble Space Telescope was launched there have been so many startlingly beautiful PN images that I have lost count of them all. For astronomers like me who study PN, all that attention has been both a blessing and a curse. Before the HST images became available, some of us foolishly thought we understood how PN formed.