Well from the official photos it looks high and narrow, but then so is the sapphire tiaras from the Turn und Taxi worn by Gloria or the Wurtemberg one worn by Diane, they seem similar to me if not more massive and they manage(d) to wear them in public too.
Maybe the Dutch one was really unbalanced or the hair of the Queen, even with extra help from extentions, could not hold the whole edifice!