How many people penned the main Voynichese text?

[rikforto]

If someone wrote the Manuscript in bursts, over the course of decades, that could also plausibly explain the variations in topics ("languages") and handwriting style.

I am also of that opinion.

Again, this is possible. But why would this explanation be preferred over the usual assumption in manuscript descriptions that different hands = different people?

When talking about 2-5 hands, I think there is a false parsimony in saying that one hand = one scribe is a simpler explanation. When the handwriting is very close, handwriting change over time is at least as good as, and arguably even better than, positing more scribes. By contrast, I find reducing Currier's observations below two different people to require positing a radical shift in handwriting, not just some modest changes in the ductus in a few places. Like a great many Voynich things, it is certainly possible, but not in the same way that 2 people/5 hands is.