@noske Has made it quite clear in his statement
"However - What is the extra benefit (utility) you obtain from spending an extra amount of money given a menu of combinations?"
If this is taken into the account that @jcarr has offered on the variables that are able to be considered at the time of Cartridge Design, and if a Supply Chain Member can deliver the wanted component as a Off the the Shelf Part, or a Bespoke Produced Part, will most likely determine that extra monies will be added to the end product .
Unfortunately for the Cartridge user the extra benefits of the assemblies produced to complete a Cartridge Range of Models, will be limited to the Manufacturers assessment, once the measurements are satisfied the end Sonic Trait will be determined by their methods of Subjective Listening Tests and a Verdict offered.
It is the Manufacturers Verdict on the unique Sonic Traits, i.e, their assessment of where a addition or removal of transparency is noticed, that will filter down into the Marketing Literature and Sales Spiel for each Model in the range.
In most cases a Range of Cartridges that has a Parent Cartridge and a Off Spring of Variants from the Parent Cart' will have the Off Spring Cart's produced with less parts or lesser parts, i.e, Aluminium replacing Boron, or a Styli Shape and Brand, lesser Quality Damping or Suspension, and in some cases the production cost cut will extend to the Magnet Material being different.
All in all, a MC Cartridge of certain Values will be placed in a area of Marketing where the Low Sales Volume will be counteracted with High Mark Up to the sale price.
It is this Marketing Method, and not limited to a Cartridge Only, that creates a mind set where the Buyer has to justify the cost of such a luxurious item as a purchase, and the fantastical spiel follows, where such items are exalted to Holy Grail Status, where one must aspire to reach.
The reality is that certain Bespoke Produced Cartridges, are seen to be reported on as an incremental improvement, over Cartridges that can be referred to as a design from a Manufacture with increased productivity and larger volume production.
It is quite important to take on board that nearly all assessments that are are offered and discovered when a interest arises, are resulting from a subjective evaluation and an individuals assessment. It is quite important for a Prospective Customer of an Item, to carry out their own assessment and make their own evaluations.