The actual reason the water beads up on the sapphire is because the sapphire crystals are processed (typically) to a higher level of smoothness - compared to mineral glass. The theory of electrons / molecular differences was just a theory, it's the level of polishing that makes all the difference. Microscopically, a mineral glass surface has deeper pits that 'tease' the surface tension of the water bead, causing it to want to spread out. Polish those micro pits out and a mineral glass will perform just like the sapphire in the test. Sapphire being so much harder than glass, it needs a completely different polishing process, the price point supports that the sapphire crystal makers will do a better job - by default.
Want more proof, buy a good quality camera lens filter, place a drop of water on the surface and compare to a sapphire crystal, doubt that you could tell a difference. Why does the mineral glass camera filter perform so well? it's processed to achieve optical purity, perfect flatness, just as much attention to making as a sapphire watch crystal.
I was also a early promoter of the water bead theory, but I learned more and changed my views. One point, if you want to compare, both crystals must be clean.