It is supply and demand.
Consider that it would only take 6 months or so to add capacity for major orders there is no demand.
Supply is certainly there otherwise there would certainly have been no Sony Vita.
Samsung are certainly supplying enough demand, in fact if delivery is now only 5-7 days they ahead of demand.
With others sticking to lower resolutions it is certainly cost effective to stick with the one supplier rather than have minor but subtle variances from each supply chain.
Anyway, its all made up. What do we/they know?