All medals has no runs. Why is this the case? Is it the fact that it's too similar to 100%?

I don't know if you fully read the requirements but it's estimated that All Medals could take at least over 20 hours, most of which (probably 14+ hours) is grinding the Scarescraper/Thrill Tower for boss ghosts. And even though you can do the run segmented, nobody really wants to because it would just still be very annoying.

Thanks for the information. It is in some way true 100% but that's just me.