Jan,
Thank you so much for injecting some real numbers into this discussion.
I certainly had no idea that there was such a large safari travelers market.
That creates a big premium optics opportunity.
Here in the Eastern US, hunting is the 'real man's' sport, with maybe 20 million participants. We are plagued with an absurd abundance of white tailed deer (no natural predators left), so hunting is easy and even cost effective. (The deer get up to 200 pounds, 40 pounds of meat from a carcass is possible.)
The preference for 10x binoculars among US hunters may simply reflect the other factor in deer hunting here, the desire for a 10 point or better rack.
A 6-7x glass will offer a wider field, arguably more useful in the bush, but the 10x will show the rack in better detail.
In theory, there are 50 million bird watchers in this country, by Audubon count, but that includes many who just put out some seed occasionally. Active birders are a much smaller group, maybe a tenth that number or less.
Most are not wealthy, so they buy what they can afford, not alphas.
Based on your input, I'd expect the US binocular mix to be much leaner than what you are achieving in Holland. Maybe ProudPapa would chime in and either destroy or verify this conclusion.