Hi Turtlebed,
It may be the result of several factors. Part of it may be the result of some of the issues mentioned in post #2 here and some may be because they are more focused on selling their own “branded” Dunlop latex in the mattresses they make and wholesale to other retailers and like many manufacturers who sell one or the other type of latex they may want their customers to feel better about the choices they offer and sometimes this is at the expense of the ones they either don’t or are phasing out.
Their basic premise that Dunlop is more durable than Talalay isn’t accurate unless there are mitigating circumstances that are the exception rather than the rule (in either direction). There is more about the different types and blends of latex in post #6 here. Both blended Talalay and natural Dunlop have a very long history of being used in mattresses that have lasted decades (see post #9 here).
Phoenix