I have resisted the urger to contact Linn asking them the simple question "Can their dealers pick and choose which equipment they 'support'?"
Support your local dealer - ha ha
What a Linn dealer stocks was historically a bone of contention for a while back in the day.
I guess now they can sell what they want.
Not sure I see your problem, the dealer in question is presumably buying stock they choose because they basically like the manufacturer, like the product(s) and believe they fill a gap in their overall product range.
Relatively few dealers will stock everything from any given manufacturer, where they are doing so, they'll typically get a better base trade price as a 'premium dealer,' or a retrospective discount, or demo stock on loan or at a discount – or any combination of those. Let's not forget hifi dealerships are businesses, not evangelical crusades (well, again on a bit of a sticky wicket there with Linn, but bear with me).
You seem to be suggesting that a Linn (or anybody else) dealer should be compelled to stock the entire range? Very few manufacturers have a similar level of expertise across multiple product types, often dealers will carry a brand to stock a particular type of product or range and may not much fancy some of the other kit wearing the same badge.
What if they don't like a product or consider there are superior alternatives? Is it then the hallmark of a 'good' dealer that they'll sell you something they don't rate just because it's dead stock (and dead cash) for them otherwise?
Just out of curiosity, did you ask why the dealer doesn't carry the device you were interested in?