a) the Minerva finish was a lot less in quality than the MB-Minerva finish. I don't think they would have upgraded Minerva without the MB logo
b) this price point was something that Minerva could not justify - an upgrade in finish and branding was thought to be necessary
The fact that the general market has not appreciated the branding to full extent is a pity, but imo there were some not so good decisions after 2014 that lead to the point we are right now. It is hypothetical whether a pure Minerva brand would have performed better in this haut horlogerie market - i sincerely doubt it.