Earlier quoted context omitted.
Well, it certainly point toward a rich patron in any case, someone who could afford all this manual labour. But what is more likely? That this is a forgotten language of which only a single mystifying example exists (ignoring the completely unlikely plants being described in the manuscript), or that it is a work of fantasy that has merits of its own?
A botanist disagrees with your assessment of the plants described in the Manuscript: http://phys.org/news/2014-02-botanists-voynich-similar-mexic...
Beside, that doesn't detract from the fact that the author of the manuscript could still have found inspiration into existing plants, imagination doesn't preclude a basis in reality.
Maybe the manuscript was written in Mexico. Maybe it is written in a cypher to obfuscate the fact that some of its content might be believed to be heretical (it contains a fair amount of naked women and appears to have some diagrams and illustrations that may relate to a theory of the origins of life or an animistic explanation of natural phenomena).
In an case, it's certainly an interesting subject of research, but I still think that the possibility of it being a work of pure fiction, maybe for the sole amusement of an eccentric rich patron, is a possibility.