I've never seen a proper analysis (it probably doesn't even exist) but I'd bet a penny to a pinch of salt that Lubrizol is by far and away the biggest global supplier of VIIs.
However this has naff all to do with Lubrizol being 'an acknowledged market leader' & everything to do with the self-serving restrictions on how oils & additive systems get 'approved'. An 'approval' specifically applies to DI A with VII B in Base Oil C in Viscosity Grade D.
Now you can easily convince yourself that say, all 22 SSI amorphous OCPs are essentially the same. However any API, ACEA or OEM approval will only apply to a specific, 'named' 22 SSI amorphous OCP. If you sell gargantuan amounts of DI & link the approval tests to your own specific, named VII, you scoop the pot because customers can't substitute Joe Bloggs Chemicals identical VII even if Joe Bloggs were giving it away free of charge!