I suppose sharing of mitochondria would explain why the number of glial cells corresponds linearly to brain volume rather than scaling with the number of neurons. When you think about it extremely long cells like neurons do have a problem with control and intra-cellular tranfer of organelles would solve a lot of problems. I'm not at all sure about other aspects of that article but it's in the nature of man to be mistaken about some things while they are correct about others.

I've also been surprised to read about genetic differences between brain cells recently that are as large as the genetic differences between immune cells and far larger than the normal sort of somatic mosaicism you get by typical errors copying that you see in other organs.