16x10 is better...but more expensive. That is where the change happened. Manufactures are setup to make panels in the most widely available because less waste for them and more profit. Basically the Market drove the state we are in now.
If no one bought 16:9 then manufactures wouldn't make it. So through marketing, pricing and purchasing the market conditions are why 16:10 never gained a strong foot hold.
"The primary reason for this move was considered to be production efficiency
[3][7] - since display panels for TVs use the
16:9 aspect ratio, it became more efficient for display manufacturers to produce computer display panels in the same aspect ratio as well.
[8] A 2008 report by DisplaySearch also cited a number of other reasons, including the ability for PC and monitor manufacturers to expand their product ranges by offering products with wider screens and higher
resolutions, helping consumers to adopt such products more easily and "stimulating the growth of the notebook PC and LCD monitor market"."